WorldWideScience

Sample records for amorphous ge bipolar

  1. Neutron diffraction studies of atomic structures of amorphous Fe-Ge and Ni-Ge alloys

    International Nuclear Information System (INIS)

    Yamada, Kazuyoshi; Endoh, Yasuo; Ishikawa, Yoshikazu; Watanabe, Noboru.

    1980-01-01

    The structures of Ge rich amorphous Fe-Ge and Ni-Ge alloys were studied by pulsed neutron total scattering. The partial structure factors of S sub(GeGe)(Q), S sub(NiGe)(Q) and S sub(NiNi)(Q) were determined successfully by using Ni 60 isotope for the Ni-Ge alloys. The Ge atoms in the 10 at% Ni-Ge amorphous alloy were found to construct a similar atomic structure as that of the amorphous Ge, while the intermediate short range order configuration between the tetrahedral random network (TRN) and the dense random packing (DRP) structure was found for the 30 at% Ni-Ge alloy. The Ge-Ge pair correlation for this intermediate short range order could well be reproduced by the modified Ge II microcrystalline model. (author)

  2. Density measurement of amorphous SixGe1-x alloys

    International Nuclear Information System (INIS)

    Laaziri, K.; Roorda, S.; Cliche, L.

    1994-01-01

    The atomic density of amorphous Si x Ge 1-x alloys (x = 1, 0.85, 0.67, 0.50, 0.20 and 0) has been measured. Mono-crystalline Si x Ge 1-x layers were implanted with 1.50-2.75 MeV Si 2+ and Ge 2+ ions to produce the amorphous material. Using surface profilometry and RBS/channeling, it was found that amorphous alloys are less dense than the crystalline alloys, and that Vegard's law underestimates the a-Si x Ge 1-x density. (orig.)

  3. Hall Mobility of Amorphous Ge2Sb2Te5

    National Research Council Canada - National Science Library

    Baily, S. A; Emin, David; Li, Heng

    2006-01-01

    The electrical conductivity, Seebeck coefficient, and Hall coefficient of 3 micron thick films of amorphous Ge2Sb2Te5 have been measured as functions of temperature from room temperature down to as low as 200 K...

  4. Local atomic environment in amorphous Ge15Te85

    Science.gov (United States)

    Jóvári, P.; Kaban, I.; Hoyer, W.; Delaplane, R. G.; Wannberg, A.

    2005-03-01

    The structure of amorphous Ge15Te85 has been studied by neutron and x-ray diffraction. Experimental data have been modelled simultaneously with the reverse Monte Carlo simulation method. The contrast between structure factors together with the application of some plausible physical constraints allowed the separation of the three partial pair correlation functions and determination of Ge and Te local environment.

  5. Structural origin of resistance drift in amorphous GeTe

    Science.gov (United States)

    Zipoli, Federico; Krebs, Daniel; Curioni, Alessandro

    2016-03-01

    We used atomistic simulations to study the origin of the change of resistance over time in the amorphous phase of GeTe, a prototypical phase-change material (PCM). Understanding the cause of resistance drift is one of the biggest challenges to improve multilevel storage technology. For this purpose, we generated amorphous structures via classical molecular-dynamics simulations under conditions as close as possible to the experimental operating ones of such memory devices. Moreover, we used the replica-exchange technique to generate structures comparable with those obtained in the experiment after long annealing that show an increase of resistance. This framework allowed us to overcome the main limitation of previous simulations, based on density-functional theory, that suffered from being computationally too expensive therefore limited to the nanosecond time scale. We found that resistance drift is caused by consumption of Ge atom clusters in which the coordination of at least one Ge atom differs from that of the crystalline phase and by removal of stretched bonds in the amorphous network, leading to a shift of the Fermi level towards the middle of the band gap. These results show that one route to design better memory devices based on current chalcogenide alloys is to reduce the resistance drift by increasing the rigidity of the amorphous network.

  6. Superconducting properties of amorphous Zr-Ge binary alloys

    International Nuclear Information System (INIS)

    Inoue, A.; Takahashi, Y.; Toyota, N.; Fukase, T.; Masumoto, T.

    1982-01-01

    A new type of refractory metal-metalloid amorphous alloys exhibiting superconductivity has been found in a binary Zr-Ge system by a modified melt-spinning technique. Specimens are in the form of continuous ribbons 1 to 2 mm wide and 0.02 to 0.03 mm thick. The germanium content in the amorphous alloys is limited to the range of 13 to 21 at%. These amorphous alloys are so ductile that no cracks are observed even after closely contacted bending test. Data are reported for various alloy compositions for the Vickers hardness and crystallization temperature, the tensile fracture strength, superconducting transition temperature Tsub(c), upper critical magnetic field, critical current density in the absence of an applied field, upper critical field gradient at Tsub(c) and the electrical resistivity at 4.2 K. The Ginzburg-Landau (GL) parameter and the GL coherence length were estimated to be 72 to 111 and about 7.9 nm, respectively, from these experimental values by using the Ginzburg-Landau-Abrikosov-Gorkov theory and hence it is concluded that the Zr-Ge amorphous alloys are extremely 'soft' type-II superconductor with high degree of dirtiness which possesses the Tsub(c) values higher than zirconium metal, in addition to high strength combined with good ductility. (author)

  7. Ge nitride formation in N-doped amorphous Ge2Sb2Te5

    International Nuclear Information System (INIS)

    Jung, M.-C.; Lee, Y. M.; Kim, H.-D.; Kim, M. G.; Shin, H. J.; Kim, K. H.; Song, S. A.; Jeong, H. S.; Ko, C. H.; Han, M.

    2007-01-01

    The chemical state of N in N-doped amorphous Ge 2 Sb 2 Te 5 (a-GST) samples with 0-14.3 N at. % doping concentrations was investigated by high-resolution x-ray photoelectron spectroscopy (HRXPS) and Ge K-edge x-ray absorption spectroscopy (XAS). HRXPS showed negligible change in the Te 4d and Sb 4d core-level spectra. In the Ge 3d core-level spectra, a Ge nitride (GeN x ) peak developed at the binding energy of 30.2 eV and increased in intensity as the N-doping concentration increased. Generation of GeN x was confirmed by the Ge K-edge absorption spectra. These results indicate that the N atoms bonded with the Ge atoms to form GeN x , rather than bonding with the Te or Sb atoms. It has been suggested that the formation of Ge nitride results in increased resistance and phase-change temperature

  8. Amorphous Ge quantum dots embedded in SiO2 formed by low energy ion implantation

    International Nuclear Information System (INIS)

    Zhao, J. P.; Huang, D. X.; Jacobson, A. J.; Chen, Z. Y.; Makarenkov, B.; Chu, W. K.; Bahrim, B.; Rabalais, J. W.

    2008-01-01

    Under ultrahigh vacuum conditions, extremely small Ge nanodots embedded in SiO 2 , i.e., Ge-SiO 2 quantum dot composites, have been formed by ion implantation of 74 Ge + isotope into (0001) Z-cut quartz at a low kinetic energy of 9 keV using varying implantation temperatures. Transmission electron microscopy (TEM) images and micro-Raman scattering show that amorphous Ge nanodots are formed at all temperatures. The formation of amorphous Ge nanodots is different from reported crystalline Ge nanodot formation by high energy ion implantation followed by a necessary high temperature annealing process. At room temperature, a confined spatial distribution of the amorphous Ge nanodots can be obtained. Ge inward diffusion was found to be significantly enhanced by a synergetic effect of high implantation temperature and preferential sputtering of surface oxygen, which induced a much wider and deeper Ge nanodot distribution at elevated implantation temperature. The bimodal size distribution that is often observed in high energy implantation was not observed in the present study. Cross-sectional TEM observation and the depth profile of Ge atoms in SiO 2 obtained from x-ray photoelectron spectra revealed a critical Ge concentration for observable amorphous nanodot formation. The mechanism of formation of amorphous Ge nanodots and the change in spatial distribution with implantation temperature are discussed

  9. Molecular dynamics simulation of ion-beam-amorphization of Si, Ge and GaAs

    CERN Document Server

    Nord, J D; Keinonen, J

    2002-01-01

    We use molecular dynamics simulations to study ion-irradiation-induced amorphization in Si, Ge and GaAs using several different interatomic force models. We find that the coordination number is higher, and the average bond length longer, for the irradiated amorphous structures than for the molten ones in Si and Ge. For amorphous GaAs, we suggest that longer Ga-Ga bonds, also present in pure Ga, are produced during the irradiation. In Si the amorphization is found to proceed via growth of amorphous regions, and low energy recoils are found to induce athermal recrystallization during irradiation.

  10. Heat capacity of amorphous and disordered Nb3Ge thin films

    International Nuclear Information System (INIS)

    Rao, N.A.H.K.

    1979-06-01

    Heat capacity measurements on 1000 to 1500A thick amorphous Nb 3 Ge and granular Al films have been carried out using an ac technique. The major goal of the experiment was to study the effect of thermal fluctuations, both above and below the superconducting transition temperature T/sub c/, in dirty, short meanfree path materials

  11. Schottky barrier formation at amorphous-crystalline interfaces of GeSb phase change materials

    NARCIS (Netherlands)

    Kroezen, H. J.; Eising, G.; ten Brink, Gert; Palasantzas, G.; Kooi, B. J.; Pauza, A.

    2012-01-01

    The electrical properties of amorphous-crystalline interfaces in phase change materials, which are important for rewritable optical data storage and for random access memory devices, have been investigated by surface scanning potential microscopy. Analysis of GeSb systems indicates that the surface

  12. Effect of mixed Ge/Si cross-linking on the physical properties of amorphous Ge-Si-Te networks

    Science.gov (United States)

    Gunasekera, K.; Boolchand, P.; Micoulaut, M.

    2014-04-01

    Amorphous GexSixTe1-2x glasses are studied as a function of composition by a combination of experimental and theoretical methods, allowing for a full description of the network structure in relationship with physico-chemical properties. Calorimetric and thermal measurements reveal that such glasses display an anomalous behavior across a range of compositions xc1=7.5% and Molecular Dynamics at selected compositions (Ge20Te80, Si20Te80, and Ge10Si10Te80). The numerical models reveal the quite different roles played by the modifier or network cross-linker Ge or Si atoms, Si being more tetrahedral in sp3 geometry, whereas Mössbauer spectroscopy shows that the nature of chemical bonding is dramatically changed around x ≃ 8%. The precise evolution of the local structure and chemical bonding ultimately allows understanding the origin of the intermediate phase in these complex tellurides.

  13. Nanocrystals and amorphous matrix phase studies of Finemet-like alloys containing Ge

    Energy Technology Data Exchange (ETDEWEB)

    Moya, J.A., E-mail: jmoya.fi.uba@gmail.co [IESIING, Facultad de Ingenieria e Informatica, UCASAL, A4402FYP Salta (Argentina); Lab. Solidos Amorfos, Facultad de Ingenieria, INTECIN, UBA-CONICET (Argentina); CONICET (Argentina)

    2010-07-15

    Two simple models were developed in order to determine the chemical composition of both nanocrystals and intergranular amorphous phases in nanocrystallized Fe{sub 73.5}Si{sub 13.5}B{sub 9}Nb{sub 3}Cu{sub 1} containing Ge using data from X-ray diffraction and Moessbauer spectroscopy techniques. Saturation magnetization of the amorphous intergranular matrix (M{sub s}{sup am}) was calculated considering the contribution of the alpha-Fe(Si,Ge) nanocrystals and saturation magnetization of the alloys. The behavior of M{sub s}{sup am} with the iron content of the matrix was obtained and discussed. The exchange stiffness constant for the nanograins and for the amorphous phases was determined. The increment in the coercive field (H{sub c}) with increasing Ge content was evaluated using two theoretical models for the random magnetocrystalline anisotropy constant (). Results show that the magnetic hardening observed could not be attributed to an increase in but mainly to an important increment of the magnetostriction constant of the alpha-Fe(Si,Ge) nanocrystals (lambda{sub s}{sup cr}). Values for lambda{sub s}{sup cr} are proposed.

  14. Optical and structural properties of Ge-Ga-Te amorphous thin films fabricated by magnetron sputtering

    Science.gov (United States)

    Dong, Ning; Chen, Yimin; Wei, Ningning; Wang, Guoxiang; Wang, Rongping; Shen, Xiang; Dai, Shixun; Nie, Qiuhua

    2017-11-01

    We deposited amorphous Ge-Ga-Te thin films by the magnetron sputtering method, and investigated the corresponding structural and optical properties by various diagnosis tools. The as-deposited film is amorphous, while crystalline features appear gradually with increasing annealing temperature. The optical band-gap and refractive index for the as-deposited and annealed films were analyzed as a function of chemical composition. It was also found that, with increasing Te and decreasing Ge and Ga content, the films usually exhibited a higher refractive index as well as a smaller optical band gap, and the optical band gap decreased with increasing annealing temperature. These results are useful to the fabrication of integrated optical devices for the biomedical sensing applications.

  15. Tuning the properties of Ge-quantum dots superlattices in amorphous silica matrix through deposition conditions

    Energy Technology Data Exchange (ETDEWEB)

    Pinto, S. [University of Minho, Portugal; Roldan Gutierrez, Manuel A [ORNL; Ramos, M. M.D. [University of Minho, Portugal; Gomes, M.J.M. [University of Minho, Portugal; Molina, S. I. [Universidad de Cadiz, Spain; Pennycook, Stephen J [ORNL; Varela del Arco, Maria [ORNL; Buljan, M. [R. Boskovic Institute, Zagreb, Croatia; Barradas, N. [Instituto Tecnologico e Nuclear (ITN), Lisbon, Portugal; Alves, E. [Instituto Tecnologico e Nuclear (ITN), Lisbon, Portugal; Chahboun, A. [FST Tanger, Morocco; Bernstorff, S. [Sincrotrone Trieste, Basovizza, Italy

    2012-01-01

    In this work, we investigate the structural properties of Ge quantum dot lattices in amorphous silica matrix, prepared by low-temperature magnetron sputtering deposition of (Ge+SiO{sub 2})/SiO{sub 2} multilayers. The dependence of quantum dot shape, size, separation, and arrangement type on the Ge-rich (Ge + SiO{sub 2}) layer thickness is studied. We show that the quantum dots are elongated along the growth direction, perpendicular to the multilayer surface. The size of the quantum dots and their separation along the growth direction can be tuned by changing the Ge-rich layer thickness. The average value of the quantum dots size along the lateral (in-plane) direction along with their lateral separation is not affected by the thickness of the Ge-rich layer. However, the thickness of the Ge-rich layer significantly affects the quantum dot ordering. In addition, we investigate the dependence of the multilayer average atomic composition and also the quantum dot crystalline quality on the deposition parameters.

  16. Tuning the properties of Ge-quantum dots superlattices in amorphous silica matrix through deposition conditions

    Energy Technology Data Exchange (ETDEWEB)

    Pinto, S. R. C.; Ramos, M. M. D.; Gomes, M. J. M. [University of Minho, Centre of Physics and Physics Department, Braga 4710-057 (Portugal); Buljan, M. [Ruder Boskovic Institute, Bijenicka cesta 54, Zagreb 10000 (Croatia); Chahboun, A. [University of Minho, Centre of Physics and Physics Department, Braga 4710-057 (Portugal); Physics Department, FST Tanger, Tanger BP 416 (Morocco); Roldan, M. A.; Molina, S. I. [Departamento de Ciencia de los Materiales e Ing. Metalurgica y Q. I., Universidad de Cadiz, Cadiz (Spain); Bernstorff, S. [Sincrotrone Trieste, SS 14 km163, 5, Basovizza 34012 (Italy); Varela, M.; Pennycook, S. J. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Barradas, N. P.; Alves, E. [Instituto Superior Tecnico e Instituto Tecnologico e Nuclear-, EN10, Sacavem 2686-953 (Portugal)

    2012-04-01

    In this work, we investigate the structural properties of Ge quantum dot lattices in amorphous silica matrix, prepared by low-temperature magnetron sputtering deposition of (Ge+SiO{sub 2})/SiO{sub 2} multilayers. The dependence of quantum dot shape, size, separation, and arrangement type on the Ge-rich (Ge + SiO{sub 2}) layer thickness is studied. We show that the quantum dots are elongated along the growth direction, perpendicular to the multilayer surface. The size of the quantum dots and their separation along the growth direction can be tuned by changing the Ge-rich layer thickness. The average value of the quantum dots size along the lateral (in-plane) direction along with their lateral separation is not affected by the thickness of the Ge-rich layer. However, the thickness of the Ge-rich layer significantly affects the quantum dot ordering. In addition, we investigate the dependence of the multilayer average atomic composition and also the quantum dot crystalline quality on the deposition parameters.

  17. Tuning the properties of Ge-quantum dots superlattices in amorphous silica matrix through deposition conditions

    International Nuclear Information System (INIS)

    Pinto, S. R. C.; Ramos, M. M. D.; Gomes, M. J. M.; Buljan, M.; Chahboun, A.; Roldan, M. A.; Molina, S. I.; Bernstorff, S.; Varela, M.; Pennycook, S. J.; Barradas, N. P.; Alves, E.

    2012-01-01

    In this work, we investigate the structural properties of Ge quantum dot lattices in amorphous silica matrix, prepared by low-temperature magnetron sputtering deposition of (Ge+SiO 2 )/SiO 2 multilayers. The dependence of quantum dot shape, size, separation, and arrangement type on the Ge-rich (Ge + SiO 2 ) layer thickness is studied. We show that the quantum dots are elongated along the growth direction, perpendicular to the multilayer surface. The size of the quantum dots and their separation along the growth direction can be tuned by changing the Ge-rich layer thickness. The average value of the quantum dots size along the lateral (in-plane) direction along with their lateral separation is not affected by the thickness of the Ge-rich layer. However, the thickness of the Ge-rich layer significantly affects the quantum dot ordering. In addition, we investigate the dependence of the multilayer average atomic composition and also the quantum dot crystalline quality on the deposition parameters.

  18. Inverse Resistance Change Cr2Ge2Te6-Based PCRAM Enabling Ultralow-Energy Amorphization.

    Science.gov (United States)

    Hatayama, Shogo; Sutou, Yuji; Shindo, Satoshi; Saito, Yuta; Song, Yun-Heub; Ando, Daisuke; Koike, Junichi

    2018-01-24

    Phase-change random access memory (PCRAM) has attracted much attention for next-generation nonvolatile memory that can replace flash memory and can be used for storage-class memory. Generally, PCRAM relies on the change in the electrical resistance of a phase-change material between high-resistance amorphous (reset) and low-resistance crystalline (set) states. Herein, we present an inverse resistance change PCRAM with Cr 2 Ge 2 Te 6 (CrGT) that shows a high-resistance crystalline reset state and a low-resistance amorphous set state. The inverse resistance change was found to be due to a drastic decrease in the carrier density upon crystallization, which causes a large increase in contact resistivity between CrGT and the electrode. The CrGT memory cell was demonstrated to show fast reversible resistance switching with a much lower operating energy for amorphization than a Ge 2 Sb 2 Te 5 memory cell. This low operating energy in CrGT should be due to a small programmed amorphous volume, which can be realized by a high-resistance crystalline matrix and a dominant contact resistance. Simultaneously, CrGT can break the trade-off relationship between the crystallization temperature and operating speed.

  19. Amorphization threshold in Si-implanted strained SiGe alloy layers

    International Nuclear Information System (INIS)

    Simpson, T.W.; Love, D.; Endisch, E.; Goldberg, R.D.; Mitchell, I.V.; Haynes, T.E.; Baribeau, J.M.

    1994-12-01

    The authors have examined the damage produced by Si-ion implantation into strained Si 1-x Ge x epilayers. Damage accumulation in the implanted layers was monitored in situ by time-resolved reflectivity and measured by ion channeling techniques to determine the amorphization threshold in strained Si 1-x Ge x (x = 0.16 and 0.29) over the temperature range 30--110 C. The results are compared with previously reported measurements on unstrained Si 1-x Ge x , and with the simple model used to describe those results. They report here data which lend support to this model and which indicate that pre-existing strain does not enhance damage accumulation in the alloy layer

  20. Atomic scale insight into the amorphous structure of Cu doped GeTe phase-change material

    International Nuclear Information System (INIS)

    Zhang, Linchuan; Sa, Baisheng; Zhou, Jian; Sun, Zhimei; Song, Zhitang

    2014-01-01

    GeTe shows promising application as a recording material for phase-change nonvolatile memory due to its fast crystallization speed and extraordinary amorphous stability. To further improve the performance of GeTe, various transition metals, such as copper, have been doped in GeTe in recent works. However, the effect of the doped transition metals on the stability of amorphous GeTe is not known. Here, we shed light on this problem for the system of Cu doped GeTe by means of ab initio molecular dynamics calculations. Our results show that the doped Cu atoms tend to agglomerate in amorphous GeTe. Further, base on analyzing the pair correlation functions, coordination numbers and bond angle distributions, remarkable changes in the local structure of amorphous GeTe induced by Cu are obviously seen. The present work may provide some clues for understanding the effect of early transition metals on the local structure of amorphous phase-change compounds, and hence should be helpful for optimizing the structure and performance of phase-change materials by doping transition metals.

  1. Extended x-ray absorption fine structure studies of amorphous and crystalline Si-Ge alloys with synchrotron radiation

    International Nuclear Information System (INIS)

    Kajiyama, Hiroshi

    1988-01-01

    Extended X-ray absorption fine structure (EXAFS) is a powerful probe to study the local structure around the atom of a specific element. In conventional EXAFS analysis, it has been known that reliable structures are obtained with the different values of absorption edge energy for different neighboring atoms. It is shown in this study that the Ge-K edge EXAFS resulting from the Ge-Ge and Ge-Si bonds in hydrogenated amorphous Si-Ge alloys was able to be excellently explained by a unique absorption edge energy value, provided that a newly developed formula based on the spherical wave function of photoelectrons is used. The microscopic structures of hydrogenated amorphous Si-Ge alloys and crystalline Si-Ge alloys have been determined using the EXAFS method. The lengths of Ge-Ge and Ge-Si bonds were constant throughout their entire composition range, and it was found that the length of Ge-Si bond was close to the average value of the bond lengths of both Ge and Si crystals. In crystalline Si-Ge alloys, it has been shown that the bonds relaxed completely, while the lattice constant varied monotonously with the composition. (Kako, I.)

  2. Atomic-scale study of the amorphous-to-crystalline phase transition mechanism in GeTe thin films

    CERN Document Server

    Mantovan, R.; Mokhles Gerami, A.; Mølholt, T. E.; Wiemer, C.; Longo, M.; Gunnlaugsson, H. P.; Johnston, K.; Masenda, H.; Naidoo, D.; Ncube, M.; Bharuth-Ram, K.; Fanciulli, M.; Gislason, H. P.; Langouche, G.; Ólafsson, S.; Weyer, G.

    The underlying mechanism driving the structural amorphous-to-crystalline transition in Group VI chalcogenides is still a matter of debate even in the simplest GeTe system. We exploit the extreme sensitivity of 57Fe emission Mössbauer spectroscopy, following dilute implantation of 57Mn (T½ = 1.5 min) at ISOLDE/CERN, to study the electronic charge distribution in the immediate vicinity  of the 57Fe probe substituting Ge (FeGe), and to interrogate the local environment of FeGe over the amorphous-crystalline phase transition in GeTe thin films. Our results show that the local structure  of as-sputtered amorphous GeTe is a combination of tetrahedral and defect-octahedral sites. The main effect of the crystallization is the conversion from tetrahedral to defect-free octahedral sites.  We discover that only the tetrahedral fraction in amorphous GeTe participates to the change of the FeGe-Te chemical bond...

  3. The Role of the Silicon Germanium (SiGe) Heterojunction Bipolar Transistor (HBT) in Mobile Technology Platforms

    Science.gov (United States)

    2011-09-01

    1. Comparison of transistor cutoff frequency for a Si BJT and SiGe HBT over time (1...the characteristics of a SiGe HBT, and compares how SiGe fares in the worlds of the GaAs HBT and the Si bipolar junction transistors ( BJT ). 2...supremacy of the Si BJT or field effect transistor (FET) in most applications. These properties include (1) growth of comparably large Si wafers with

  4. The enhancement of the interdiffusion in Si/Ge amorphous artificial multilayers by additions of B and Au

    International Nuclear Information System (INIS)

    Park, B.; Spaepen, F.; Poate, J.M.; Jacobson, D.C.

    1990-01-01

    Amorphous Si/amorphous Ge artificial multilayers were prepared by ion beam sputtering. Boron or gold impurities were introduced into the Si/Ge multilayers by ion implantation or during the sputtering deposition. Diffusion coefficients were determined by measuring the decrease in the intensity of the first order X-ray diffraction peak resulting from the composition modulation. It was found that the interdiffusion of Si and Ge in their amorphous phase can be enhanced by doping. The enhancement factor is independent of the degree of structural relaxation, as observed by the decrease of diffusivity with annealing time, of the amorphous phase. A model is proposed that describes this behavior in terms of electronic effects, introduced by the dopants, on the pre-existing structural defects governing diffusion

  5. Enhanced Au induced lateral crystallization in electron-irradiated amorphous Ge on SiO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Sakiyama, Shin; Kaneko, Takahiro; Ootsubo, Takanobu; Sakai, Takatsugu; Nakashima, Kazutoshi; Moto, Kenta; Yoneoka, Masashi; Takakura, Kenichiro; Tsunoda, Isao, E-mail: isao_tsunoda@kumamoto-nct.ac.jp

    2014-04-30

    We have investigated the low temperature of Au induced lateral crystallization of electron irradiated amorphous Ge on SiO{sub 2}/Si substrate. The reduction of the critical annealing time to cause the Au induced lateral crystallization is realized by high energy electron irradiation. In addition, the lateral crystallization region of the sample with electron irradiation has high crystalline quality as well as the sample without electron irradiation. We have speculated that the Au induced lateral crystallization of amorphous Ge on SiO{sub 2}/Si substrate was enhanced by electron irradiation, due to the introduction of point defects into amorphous Ge able to diffuse easily of Au atoms. - Highlights: • Au induced lateral crystallization of electron irradiated Ge is investigated. • Crystallization annealing time is significantly reduced. • High crystalline quality of lateral region was not changed by electron irradiation.

  6. Atomic mobility in the overheated amorphous GeTe compound for phase change memories

    International Nuclear Information System (INIS)

    Sosso, G.C.; Behler, J.; Bernasconi, M.

    2016-01-01

    Abstractauthoren Phase change memories rest on the ability of some chalcogenide alloys to undergo a fast and reversible transition between the crystalline and amorphous phases upon Joule heating. The fast crystallization is due to a high nucleation rate and a large crystal growth velocity which are actually possible thanks to the fragility of the supercooled liquid that allows for the persistence of a high atomic mobility at high supercooling where the thermodynamical driving force for crystallization is also high. Since crystallization in the devices occurs by rapidly heating the amorphous phase, hysteretic effects might arise with a different diffusion coefficient and viscosity on heating than on cooling. In this work, we have quantified these hysteretic effects in the phase change compound GeTe by means of molecular dynamics simulations. The atomic mobility in the overheated amorphous phase is lower than in supercooled liquid at the same temperature and the viscosity is consequently higher. Still, the simulations of the overheated amorphous phase reveal a breakdown of the Stokes-Einstein relation between the diffusion coefficient and the viscosity, similarly to what we found previously in the supercooled liquid. Evidences are provided that the breakdown is due to the emergence of dynamical heterogeneities at high supercooling. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. First-principles study of nitrogen doping in cubic and amorphous Ge2Sb2Te5

    Science.gov (United States)

    Caravati, S.; Colleoni, D.; Mazzarello, R.; Kühne, T. D.; Krack, M.; Bernasconi, M.; Parrinello, M.

    2011-07-01

    We investigated the structural, electronic and vibrational properties of amorphous and cubic Ge2Sb2Te5 doped with N at 4.2 at.% by means of large scale ab initio simulations. Nitrogen can be incorporated in molecular form in both the crystalline and amorphous phases at a moderate energy cost. In contrast, insertion of N in the atomic form is very energetically costly in the crystalline phase, though it is still possible in the amorphous phase. These results support the suggestion that N segregates at the grain boundaries during the crystallization of the amorphous phase, resulting in a reduction in size of the crystalline grains and an increased crystallization temperature.

  8. Time-resolved reflection and transmission studies of amorphous Ge-Te thin-film crystallization

    Science.gov (United States)

    Libera, M.; Chen, M.

    1993-03-01

    Measurements of the temperature and time dependence of visible diode laser transmission and reflection are combined with transmission electron microscopy (TEM) to study the crystallization of two 75 nm Ge-Te thin films. Near-stoichiometric Ge48Te52 transforms by the rapid growth of crystals through the film thickness followed by 2D growth in the film plane. Changes in film reflection and transmission are directly related to the volume fraction transformed. The optical measurements are interpreted in terms of classical Johnson-Mehl-Avrami kinetics. A Kissinger analysis gives an activation energy for crystallization of 1.7 eV. Isothermal measurements lead to an Avrami exponent of 4.5. The data are modeled using a numerical temperature-dependent expression developed by Greer [Acta Metall. 30, 171 (1982)]. Off-stoichiometric Ge54Te46 films show markedly different crystallization behavior. Transmission and reflection measurements indicate that the transformation proceeds by rapid growth of a crystalline layer at the free surface of the film followed by 1D growth of this layer through the film. The observation is confirmed by TEM imaging and diffraction. This work shows that reflection and transmission measurements can be an effective method for the study of crystallization kinetics of amorphous thin films, particularly when more traditional calorimetric methods cannot be employed.

  9. The effect of fluorine in low thermal budget polysilicon emitters for SiGe heterojunction bipolar transistors

    International Nuclear Information System (INIS)

    Schiz, F.J.W.

    1999-03-01

    This thesis investigates the behaviour of fluorine in two types of polysilicon emitter. In the first type the emitter is deposited at 610 deg. C as polycrystalline silicon (p-Si). In the second type the emitter is deposited at 560 deg. C as amorphous silicon (α-Si). The amorphous silicon 1 then regrows to polysilicon during subsequent high temperature anneals. Remarkably different behaviour of fluorine is seen in as-deposited α-Si and as-deposited p-Si emitter bipolar transistors. In the most extreme case, fluorine-implanted as-deposited p-Si devices show a base current increase by a factor of 1.5 and equivalent α-Si devices a base current decrease by a factor of 10.0 compared to unimplanted devices. Cross-section TEM observations are made to study the structure of the polysilicon/silicon interface and SIMS measurements to study the distribution of the fluorine in the polysilicon. The TEM results correlate well with the electrical results and show that fluorine accelerates interfacial oxide breakup. Furthermore, they show that for a given thermal budget, more interfacial oxide breakup and thus more epitaxial regrowth is obtained for transistors with p-Si polysilicon emitters. This results in a lower emitter resistance, for example as low as 12Ωμm 2 for as-deposited p-Si devices. The base current suppression for as-deposited α-Si devices is explained by fluorine passivation of trapping states at the interface. Analysis of the fluorine SIMS profiles suggests that they do not resemble normal diffusion profiles, but are due to fluorine trapped at defects. It is shown that a reciprocal relationship exists between the fluorine dose in the bulk polysilicon layer and the fluorine dose at the interface. In as-deposited α-Si devices, there is more fluorine trapped at defects in the bulk polysilicon layer, so less is available to diffuse to the interface. As a result there is less interfacial oxide breakup and more passivation in the as-deposited α-Si devices. These

  10. Magnetic and electrical transport properties of delta-doped amorphous Ge:Mn magnetic semiconductors

    International Nuclear Information System (INIS)

    Li, H.L.; Lin, H.T.; Wu, Y.H.; Liu, T.; Zhao, Z.L.; Han, G.C.; Chong, T.C.

    2006-01-01

    We report on the growth and characterization of delta-doped amorphous Ge:Mn diluted magnetic semiconductor thin films on GaAs (0 0 1) substrates. The fabricated samples exhibit different magnetic behaviors, depending on the Mn doping concentration. The Curie temperature was found to be dependent on both the Mn doping concentration and spacing between the doping layers. A sharp drop in magnetization and rise in resistivity are observed at low temperature in samples with high Mn doping concentrations, which is also accompanied by a negative thermal remanent magnetization (TRM) in the higher temperature range. The temperature at which the magnetization starts to drop and the negative TRM appears show a correlation with the Mn doping concentration. The experimental results are discussed based on the formation of ferromagnetic regions at high temperature and antiferromagnetic coupling between these regions at low temperature

  11. Optical, electrical and the related parameters of amorphous Ge-Bi-Se thin films

    International Nuclear Information System (INIS)

    El-Korashy, A.; El-Kabany, N.; El-Zahed, H.

    2005-01-01

    The related optical and electrical parameters of amorphous Ge-Bi-Se thin films were studied. The dependence of optical and electrical properties on the Bi content was observed in most compositions. At Bi >10at% the behavior show a switch from p to n type conduction mechanism. The correlation between the optical band gap E g and the average heats of atomization H s were observed. The results indicated that both the number of topological constant N con and the radial and angular N α , N β valence force constants exhibit the same trend with increasing Bi content. On the other hand, the mean bond energy increases with increasing Bi content to x=15at%. It may be concluded that is a function of the mean coordination number N co , the type of bonds, the degree of cross-linking and the band energy forming the network

  12. Chronological change of electrical resistance in GeCu2Te3 amorphous film induced by surface oxidation

    International Nuclear Information System (INIS)

    Saito, Yuta; Shindo, Satoshi; Sutou, Yuji; Koike, Junichi

    2014-01-01

    Unusual chronological electrical resistance change behavior was investigated for amorphous GeCu 2 Te 3 phase change material. More than a 1 order decrease of electrical resistance was observed in the air even at room temperature. The resistance of the amorphous film gradually increased with increasing temperature and then showed a drop upon crystallization. Such unusual behavior was attributed to the oxidation of the amorphous GeCu 2 Te 3 film. From the compositional depth profile measurement, the GeCu 2 Te 3 film without any capping layer was oxidized in air at room temperature and the formed oxide was mainly composed of germanium oxide. Consequently, a highly-conductive Cu-rich layer was formed in the vicinity of the surface of the film, which reduced the total resistance of the film. The present results could provide insight into the chronological change of electrical resistance in amorphous chalcogenide materials, indicating that not only relaxation of the amorphous, but also a large atomic diffusion contributes to the chronological resistance change. (paper)

  13. Anomalous dose rate effects in gamma irradiated SiGe heterojunction bipolar transistors

    International Nuclear Information System (INIS)

    Banerjee, G.; Niu, G.; Cressler, J.D.; Clark, S.D.; Palmer, M.J.; Ahlgren, D.C.

    1999-01-01

    Low dose rate (LDR) cobalt-60 (0.1 rad(Si)/s) gamma irradiated Silicon Germanium (SiGe) Heterojunction Bipolar Transistors (HBTs) were studied. Comparisons were made with devices irradiated with 300 rad(Si)/s gamma radiation to verify if LDR radiation is a serious radiation hardness assurance (RHA) issue. Almost no LDR degradation was observed in this technology up to 50 krad(Si). The assumption of the presence of two competing mechanisms is justified by experimental results. At low total dose (le20 krad), an anomalous base current decrease was observed which is attributed to self-annealing of deep-level traps to shallower levels. An increase in base current at larger total doses is attributed to radiation induced generation-recombination (G/R) center generation. Experiments on gate-assisted lateral PNP transistors and 2D numerical simulations using MEDICI were used to confirm these assertions

  14. Local atomic structure and chemical order in amorphous SiGe:H and SiC:H alloys

    International Nuclear Information System (INIS)

    Pisarkiewicz, T.; Stapinski, T.

    1994-01-01

    The local structure and chemical ordering in amorphous hydrogenated silicon-germanium and silicon-carbon alloys were analyzed mainly with the help of extended x-ray absorption fine structure (EXAFS) spectroscopy, Raman scattering and electron diffraction. Ge-Ge and Ge-Si distances were found to be independent of concentration and the composition of the first coordination shell around Ge is consistent with a random mixing of the two species in a-Si 1-x Ge:H alloy. The first-coordination-shell average bond lengths for Si-Si and SiC in a-Si 1-x C x :H are also constant with concentration x and the comparison of the first coordination shell composition around Si with average concentration indicates that the alloys tends to be chemically ordered. The degree of crystallinity in microcrystalline Si films determined by EXAFS is in agreement with that obtained in Raman scattering analysis. (author). 16 refs, 5 figs

  15. Raman scattering study of the a-GeTe structure and possible mechanism for the amorphous to crystal transition

    International Nuclear Information System (INIS)

    Andrikopoulos, K S; Yannopoulos, S N; Voyiatzis, G A; Kolobov, A V; Ribes, M; Tominaga, J

    2006-01-01

    We report on an inelastic (Raman) light scattering study of the local structure of amorphous GeTe (a-GeTe) films. A detailed analysis of the temperature-reduced Raman spectra has shown that appreciable structural changes occur as a function of temperature. These changes involve modifications of atomic arrangements such as to facilitate the rapid amorphous to crystal transformation, which is the major advantage of phase-change materials used in optical data storage media. A particular structural model, supported by polarization analysis, is proposed which is compatible with the experimental data as regards both the structure of a-GeTe and the crystallization transition. The remarkable difference between the Raman spectrum of the crystal and the glass can thus naturally be accounted for

  16. Copper-Based OHMIC Contracts for the Si/SiGe Heterojunction Bipolar Transistor Structure

    Science.gov (United States)

    Das, Kalyan; Hall, Harvey

    1999-01-01

    Silicon based heterojunction bipolar transistors (HBT) with SiGe base are potentially important devices for high-speed and high-frequency microelectronics. These devices are particularly attractive as they can be fabricated using standard Si processing technology. However, in order to realize the full potential of devices fabricated in this material system, it is essential to be able to form low resistance ohmic contacts using low thermal budget process steps and have full compatibility with VLSI/ULSI processing. Therefore, a study was conducted in order to better understand the contact formation and to develop optimized low resistance contacts to layers with doping densities corresponding to the p-type SiGe base and n-type Si emitter regions of the HBTS. These as-grown doped layers were implanted with BF(sub 2) up to 1 X 10(exp 16)/CM(exp 2) and As up to 5 x 10(exp 15)/CM2, both at 30 keV for the p-type SiGe base and n-type Si emitter layers, respectively, in order to produce a low sheet resistance surface layer. Standard transfer length method (TLM) contact pads on both p and n type layers were deposited using an e-beam evaporated trilayer structure of Ti/CufTi/Al (25)A/1500A/250A/1000A). The TLM pads were delineated by a photoresist lift-off procedure. These contacts in the as-deposited state were ohmic, with specific contact resistances for the highest implant doses of the order of 10(exp -7) ohm-CM2 and lower.

  17. Nature of phase transitions in crystalline and amorphous GeTe-Sb2Te3 phase change materials.

    Science.gov (United States)

    Kalkan, B; Sen, S; Clark, S M

    2011-09-28

    The thermodynamic nature of phase stabilities and transformations are investigated in crystalline and amorphous Ge(1)Sb(2)Te(4) (GST124) phase change materials as a function of pressure and temperature using high-resolution synchrotron x-ray diffraction in a diamond anvil cell. The phase transformation sequences upon compression, for cubic and hexagonal GST124 phases are found to be: cubic → amorphous → orthorhombic → bcc and hexagonal → orthorhombic → bcc. The Clapeyron slopes for melting of the hexagonal and bcc phases are negative and positive, respectively, resulting in a pressure dependent minimum in the liquidus. When taken together, the phase equilibria relations are consistent with the presence of polyamorphism in this system with the as-deposited amorphous GST phase being the low entropy low-density amorphous phase and the laser melt-quenched and high-pressure amorphized GST being the high entropy high-density amorphous phase. The metastable phase boundary between these two polyamorphic phases is expected to have a negative Clapeyron slope. © 2011 American Institute of Physics

  18. Optical properties of silver doped amorphous films of composition Ge28S72 and Ge22Ga6S72

    Czech Academy of Sciences Publication Activity Database

    Bartoš, M.; Wágner, T.; Válková, S.; Pavlišta, M.; Vlček, Milan; Beneš, L.; Frumar, M.

    2011-01-01

    Roč. 13, 11-12 (2011), 1442-1446 ISSN 1454-4164. [Fifth International Conference on Amorphous and Nanostructured Chalcogenides. Magurele - Bucharest, 26.06.2011-01.07.2011] Institutional research plan: CEZ:AV0Z40500505 Keywords : amorphous films * chalcogenides * optical properties Subject RIV: CA - Inorganic Chemistry Impact factor: 0.457, year: 2011 http://joam.inoe.ro/index.php?option=magazine&op=view&idu=2941&catid=68

  19. Long-Term Reliability of High Speed SiGe/Si Heterojunction Bipolar Transistors

    Science.gov (United States)

    Ponchak, George E. (Technical Monitor); Bhattacharya, Pallab

    2003-01-01

    Accelerated lifetime tests were performed on double-mesa structure Si/Si0.7Ge0.3/Si npn heterojunction bipolar transistors, grown by molecular beam epitaxy, in the temperature range of 175C-275C. Both single- and multiple finger transistors were tested. The single-finger transistors (with 5x20 micron sq m emitter area) have DC current gains approximately 40-50 and f(sub T) and f(sub MAX) of up to 22 GHz and 25 GHz, respectively. The multiple finger transistors (1.4 micron finger width, 9 emitter fingers with total emitter area of 403 micron sq m) have similar DC current gain but f(sub T) of 50 GHz. It is found that a gradual degradation in these devices is caused by the recombination enhanced impurity diffusion (REID) of boron atoms from the p-type base region and the associated formation of parasitic energy barriers to electron transport from the emitter to collector layers. This REID has been quantitatively modeled and explained, to the first order of approximation, and the agreement with the measured data is good. The mean time to failure (MTTF) of the devices at room temperature is estimated from the extrapolation of the Arrhenius plots of device lifetime versus reciprocal temperature. The results of the reliability tests offer valuable feedback for SiGe heterostructure design in order to improve the long-term reliability of the devices and circuits made with them. Hot electron induced degradation of the base-emitter junction was also observed during the accelerated lifetime testing. In order to improve the HBT reliability endangered by the hot electrons, deuterium sintered techniques have been proposed. The preliminary results from this study show that a deuterium-sintered HBT is, indeed, more resistant to hot-electron induced base-emitter junction degradation. SiGe/Si based amplifier circuits were also subjected to lifetime testing and we extrapolate MTTF is approximately 1.1_10(exp 6) hours at 125iC junction temperature from the circuit lifetime data.

  20. Thermally-activated internal friction peaks in amorphous films of Nb3Ge and Nb3Si

    International Nuclear Information System (INIS)

    Berry, B.S.; Pritchet, W.C.

    1978-01-01

    A large number of the thermally-activated internal friction peaks observed in crystalline solids are associated with the general mechanism of stress-induced directional short-range ordering. These peaks are an indirect but nevertheless valuable structural probe, and provide an important means of obtaining quantitative information on the kinetics of local atomic movements. This paper deals with what are thought to be the first-known examples of such peaks in the field of metallic glasses. The peaks have been observed in amorphous films of Nb 3 Ge and Nb 3 Si which are both superconductors with transition temperatures Tsub(c) near 3.6K. Although Tsub(c) is thus well below the record values of approximately equal to 23K reported for crystalline films of Nb 3 Ge, Tsuei has found the amorphous films to be much superior mechanically to their crystalline counterparts. Consequently, the amorphous films have technological interest as an easily-handled source from which the brittle high-Tsub(c) phase may be obtained by a final in-situ anneal. (author)

  1. Phenomenological analysis of random telegraph noise in amorphous TiOx-based bipolar resistive switching random access memory devices.

    Science.gov (United States)

    Lee, Jung-Kyu; Lee, Ju-Wan; Bae, Jong-Ho; Park, Jinwon; Chung, Sung-Woong; Roh, Jae Sung; Hong, Sung-Joo; Lee, Jong-Ho

    2012-07-01

    As dimensions of resistive random access memories (RRAMs) devices continue to shrink, the low-frequency noise of nanoscale devices has become increasingly important in evaluating the device reliability. Thus, we investigated random telegraph noise (RTN) caused by capture and emission of an electron at traps. We physically analyzed capture and emission processes through systematic measurements of amorphous TiOx (alpha-TiOx)-based bipolar RRAMs. RTNs were observed during high-resistance state (HRS) in most devices. However, discrete switching behavior was scarcely observed in low-resistance state (LRS) as most of traps in the alpha-TiOx were filled with mobile ions such as O2- in LRS. The capture and emission processes of an electron at traps are largely divided into two groups: (1) both capture and emission processes are mainly affected by electric field; and (2) one of the capture and emission processes is only influenced by the thermal process. This paper provides fundamental physics required to understand the mechanism of RTNs in alpha-TiOx-based bipolar RRAMs.

  2. High transmittance contrast in amorphous to hexagonal phase of Ge2Sb2Te5: Reversible NIR-window

    Science.gov (United States)

    Singh, Palwinder; Singh, A. P.; Kanda, Neetu; Mishra, Monu; Gupta, Govind; Thakur, Anup

    2017-12-01

    Ge2Sb2Te5 (GST) is one of the best phase change materials because of its splendid set of properties, viz., high thermal stability, fast crystallization speed, good endurance, scalability, and reliability. Phase transition [amorphous → face centered cubic (fcc) → hexagonal close packed (hcp)] of GST thin films with annealing was studied using X-ray diffraction. Thin films in amorphous, fcc, and hcp phases are highly, medium, and negligible transparent in the near infra-red region, respectively. The optical transmission in amorphous, fcc, and hcp phases is ˜92%, ˜46%, and ˜2%, respectively, at the wavelength of 2740 nm. At 2740 nm, a high transmission contrast (˜90%) is observed with phase transition from the amorphous to hcp phase. By utilizing large transmission contrast, it is demonstrated that GST can be availed as a potential candidate for reversible near infra-red-window. The sharp change in optical transmission with phase transition can be understood from the change in density of states in the valence band.

  3. Suppression of the superconductivity in ultrathin amorphous Mo78Ge22 films observed by STM

    Science.gov (United States)

    Lotnyk, D.; Onufriienko, O.; Samuely, T.; Shylenko, O.; Komanický, V.; Szabó, P.; Feher, A.; Samuely, P.

    2017-08-01

    In contact with a superconductor a normal metal modifies its properties due to Andreev reflection. In the current work the local density of states (LDOS) of superconductor-normal metal Mo78Ge22-Au bilayers are studied by means of STM applied from the Au side. Three bilayers have been prepared on silicate glass substrate consisting of 100, 10 and 5 nm MoGe thin films covered always by 5 nm Au layer. The tunneling spectra were measured at temperatures from 0.5 to 7 K. The two-dimensional cross-correlation between topography and normalized zero-bias conductance indicates a proximity effect between 100 and 10 nm MoGe thin films and Au layer where a superconducting gap slightly smaller than that of bulk MoGe is observed. The effect of the thinnest 5 nm MoGe layer on Au leads to much smaller gap moreover the LDOS reveals almost completely suppressed coherence peaks. This is attributed to a strong pair-breaking effect of spin-flip processes at the interface between MoGe films and the substrate.

  4. Different threshold and bipolar resistive switching mechanisms in reactively sputtered amorphous undoped and Cr-doped vanadium oxide thin films

    Science.gov (United States)

    Rupp, Jonathan A. J.; Querré, Madec; Kindsmüller, Andreas; Besland, Marie-Paule; Janod, Etienne; Dittmann, Regina; Waser, Rainer; Wouters, Dirk J.

    2018-01-01

    This study investigates resistive switching in amorphous undoped and Cr-doped vanadium oxide thin films synthesized by sputtering deposition at low oxygen partial pressure. Two different volatile threshold switching characteristics can occur as well as a non-volatile bipolar switching mechanism, depending on device stack symmetry and Cr-doping. The two threshold switching types are associated with different crystalline phases in the conduction filament created during an initial forming step. The first kind of threshold switching, observed for undoped vanadium oxide films, was, by its temperature dependence, proven to be associated with a thermally triggered insulator-to-metal transition in a crystalline VO2 phase, whereas the threshold switch observed in chromium doped films is stable up to 90 °C and shows characteristics of an electronically induced Mott transition. This different behaviour for undoped versus doped films has been attributed to an increased stability of V3+ due to the Cr3+ doping (as evidenced by X-ray photoelectron spectroscopy analysis), probably favouring the creation of a crystalline Cr-doped V2O3 phase (rather than a Cr-doped VO2 phase) during the energetic forming step. The symmetric Pt/a-(VCr)Ox/Pt device showing high temperature stable threshold switching may find interesting applications as a possible new selector device for resistive switching memory (ReRAM) crossbar arrays.

  5. Textured Sb2Te3 films and GeTe/Sb2Te3 superlattices grown on amorphous substrates by molecular beam epitaxy

    NARCIS (Netherlands)

    Boschker, Jos E.; Tisbi, E.; Placidi, E.; Momand, Jamo; Redaelli, Andrea; Kooi, Bart J.; Arciprete, Fabrizio; Calarco, Raffaella

    The realization of textured films of 2-dimensionally (2D) bonded materials on amorphous substrates is important for the integration of this material class with silicon based technology. Here, we demonstrate the successful growth by molecular beam epitaxy of textured Sb2Te3 films and GeTe/Sb2Te3

  6. Reversible electrical resistance switching in GeSbTe thin films : An electrolytic approach without amorphous-crystalline phase-change

    NARCIS (Netherlands)

    Pandian, Ramanathaswamy; Kooi, Bart J.; Palasantzas, George; De Hosson, Jeff Th. M.; Wouters, DJ; Hong, S; Soss, S; Auciello, O

    2008-01-01

    Besides the well-known resistance switching originating from the amorphous-crystalline phase-change in GeSbTe thin films, we demonstrate another switching mechanism named 'polarity-dependent resistance (PDR) switching'. 'Me electrical resistance of the film switches between a low- and high-state

  7. Two-zone SiGe base heterojunction bipolar charge plasma transistor for next generation analog and RF applications

    Science.gov (United States)

    Bramhane, Lokesh Kumar; Singh, Jawar

    2017-01-01

    For next generation terahertz applications, heterojunction bipolar transistor (HBT) with reduced dimensions and charge plasma (CP) can be a potential candidate due to simplified and inexpensive process. In this paper, a symmetric lateral two-zone SiGe base heterojunction bipolar charge plasma transistor (HBCPT) with an extruded (extended) base is proposed and its performance at circuit level is studied. The linearly graded electric field in the proposed HBCPT provides improved self gain (β) and cut-off frequency (fT). Two-dimensional (2-D) TCAD and small-signal model based simulations of the proposed HBCPT demonstrates high self gain β 35-172.93 and fT of 1-4 THz for different device parameters. Moreover, fT of 1104.9 GHz and β of 35 can be achieved by decreasing Nb up to 8.2 ×1017cm-3 . Although, fT of 2 THz and 4 THz can also be achieved by reducing the base resistance up to 10 Ω and increasing the emitter/collector length up to 63 nm, respectively. The small-signal analysis of common-emitter amplifier based on the proposed HBCPT demonstrate high voltage gain of 50.11 as compared to conventional HBT (18.1).

  8. Transport properties of the pressure-induced amorphous semiconductor state of Al sub 3 sub 2 Ge sub 6 sub 8

    CERN Document Server

    Antonov, V E; Gurov, A F; Harkunov, A I; Kolyubakin, A I

    2002-01-01

    The temperature dependences of the dc conductivity and thermopower of the bulk amorphous alloy Al sub 3 sub 2 Ge sub 6 sub 8 were investigated at 6-420 K and at 80-370 K, respectively. The samples were prepared by solid-state amorphization of a quenched crystalline high-pressure phase while heating from 77 to 400 K at ambient pressure. Amorphous Al sub 3 sub 2 Ge sub 6 sub 8 was found to be a p-type semiconductor with an unusual combination of transport properties. The behaviour of the properties was described semi-quantitatively in terms of a modified Mott-Davis model assuming that the Fermi level lies inside the valence band tail.

  9. First-principles study of crystalline and amorphous Ge{sub 2}Sb{sub 2}Te{sub 5} and the effects of stoichiometric defects

    Energy Technology Data Exchange (ETDEWEB)

    Caravati, S; Bernasconi, M [Dipartimento di Scienza dei Materiali, Universita di Milano-Bicocca, Via R Cozzi 53, I-20125, Milano (Italy); Kuehne, T D; Parrinello, M [Department of Chemistry and Applied Biosciences, ETH Zurich, USI Campus, Via Giuseppe Buffi 13, CH-6900 Lugano (Switzerland); Krack, M [Paul Scherrer Institut, CH-5232 Villigen (Switzerland)], E-mail: marco.bernasconi@mater.unimib.it

    2009-06-24

    Based on ab initio molecular dynamics simulations, we investigated the structural, electronic and vibrational properties of cubic and amorphous Ge{sub 2}Sb{sub 2}Te{sub 5} (GST) phase change material, focusing in particular on the effects of defects in stoichiometry on the electronic properties. It turned out Ge/Sb deficiencies (excess) in the cubic phase induce a shift of the Fermi level inside the valence (conduction) bands. In contrast, the amorphous network is flexible enough to accommodate defects in stoichiometry, keeping the Fermi level pinned at the center of the bandgap (at zero temperature). Changes in the structural and electronic properties induced by the use of hybrid functionals (HSE03, PBE0) instead of gradient corrected functionals (PBE) are addressed as well. Analysis of vibrational spectra and Debye-Waller factors of cubic and amorphous GST is also presented.

  10. Ge-Ga-Sb-S amorphous chalcogenides doped with rare – earth elements

    Czech Academy of Sciences Publication Activity Database

    Střižík, L.; Wágner, T.; Heo, J.; Liu, C.; Pavlišta, M.; Přikryl, J.; Frumarová, Božena; Frumar, M.

    2012-01-01

    Roč. 106, č. S4 (2012), s1206 ISSN 0009-2770. [4th EuCheMS Chemistry Congress. 26.08.2012-30.08.2012, Prague] R&D Projects: GA MŠk(CZ) LH11101 Institutional support: RVO:61389013 Keywords : Ga-Ge-Sb-S * rare - earth s * luminescence Subject RIV: CA - Inorganic Chemistry www.euchems-prague2012.cz

  11. First-principles study of nitrogen doping in cubic and amorphous Ge{sub 2}Sb{sub 2}Te{sub 5}

    Energy Technology Data Exchange (ETDEWEB)

    Caravati, S; Mazzarello, R; Kuehne, T D; Parrinello, M [Computational Science, Department of Chemistry and Applied Biosciences, ETH Zurich, USI Campus, Via Giuseppe Buffi 13, CH-6900 Lugano (Switzerland); Colleoni, D; Bernasconi, M [Dipartimento di Scienza dei Materiali, Universita di Milano-Bicocca, Via R Cozzi 53, I-20125 Milano (Italy); Krack, M [Paul Scherrer Institut, CH-5232 Villigen (Switzerland)

    2011-07-06

    We investigated the structural, electronic and vibrational properties of amorphous and cubic Ge{sub 2}Sb{sub 2}Te{sub 5} doped with N at 4.2 at.% by means of large scale ab initio simulations. Nitrogen can be incorporated in molecular form in both the crystalline and amorphous phases at a moderate energy cost. In contrast, insertion of N in the atomic form is very energetically costly in the crystalline phase, though it is still possible in the amorphous phase. These results support the suggestion that N segregates at the grain boundaries during the crystallization of the amorphous phase, resulting in a reduction in size of the crystalline grains and an increased crystallization temperature.

  12. Crystallization and amorphization studies of a Ge 2 Sb 2.3 Te 5 thin-film sample under pulsed laser irradiation

    Science.gov (United States)

    Khulbe, Pramod K.; Xun, Xiaodong; Mansuripur, M.

    2000-05-01

    We present the results of crystallization and amorphization studies on a thin-film sample of Ge 2 Sb 2.3 Te 5 , encapsulated in a quadrilayer stack as in the media of phase-change optical disk data storage. The study was conducted on a two-laser static tester in which one laser, operating in pulsed mode, writes either amorphous marks on a crystalline film or crystalline marks on an amorphous film. The second laser, operating at low power in the cw mode, simultaneously monitors the progress of mark formation in terms of the variations of reflectivity both during the write pulse and in the subsequent cooling period. In addition to investigating some of the expected features associated with crystallization and amorphization, we noted certain curious phenomena during the mark-formation process. For example, at low-power pulsed illumination, which is insufficient to trigger the phase transition, there is a slight change in the reflectivity of the sample. This is believed to be caused by a reversible change in the complex refractive index of the Ge 2 Sb 2.3 Te 5 film in the course of heating above the ambient temperature. We also observed that the mark-formation process may continue for as long as 1 s beyond the end of the write laser pulse. This effect is especially pronounced during amorphous mark formation under high-power, long-pulse illumination.

  13. Ultra-low thermal conductivity of high-interface density Si/Ge amorphous multilayers

    Science.gov (United States)

    Goto, Masahiro; Xu, Yibin; Zhan, Tianzhuo; Sasaki, Michiko; Nishimura, Chikashi; Kinoshita, Yohei; Ishikiriyama, Mamoru

    2018-04-01

    Owing to their phonon scattering and interfacial thermal resistance (ITR) characteristics, inorganic multilayers (MLs) have attracted considerable attention for thermal barrier applications. In this study, a-Si/a-Ge MLs with layer thicknesses ranging from 0.3 to 5 nm and different interfacial elemental mixture states were fabricated using a combinatorial sputter-coating system, and their thermal conductivities were measured via a frequency-domain thermo-reflectance method. An ultra-low thermal conductivity of κ = 0.29 ± 0.01 W K‑1 m‑1 was achieved for a layer thickness of 0.8 nm. The ITR was found to decrease from 8.5 × 10‑9 to 3.6 × 10‑9 m2 K W‑1 when the interfacial density increases from 0.15 to 0.77 nm‑1.

  14. Reverse Monte Carlo simulations, Raman scattering, and thermal studies of an amorphous Ge30Se70 alloy produced by mechanical alloying.

    Science.gov (United States)

    Machado, K D; de Lima, J C; Campos, C E M; Grandi, T A; Pizani, P S

    2004-01-01

    The short- and intermediate-range orders of an amorphous Ge30Se70 alloy produced by mechanical alloying were studied by reverse Monte Carlo simulations of its x-ray total structure factor, Raman scattering, and differential scanning calorimetry. The simulations were used to compute the G(Ge-Ge) (RMC)(r), G(Ge-Se) (RMC)(r), and G(Se-Se) (RMC)(r) partial distribution functions and the S(Ge-Ge) (RMC)(K), S(Ge-Se) (RMC)(K), and S(Se-Se) (RMC)(K) partial structure factors. We calculated the coordination numbers and interatomic distances for the first and second neighbors and the bond-angle distribution functions Theta(ijl)(cos theta). The data obtained indicate that the structure of the alloy has important differences when compared to alloys prepared by other techniques. There are a high number of Se-Se pairs in the first shell, and some of the tetrahedral units formed seemed to be connected by Se-Se bridges. (c) 2004 American Institute of Physics

  15. Three-dimensional simulation of fabrication process-dependent effects on single event effects of SiGe heterojunction bipolar transistor

    International Nuclear Information System (INIS)

    Zhang Jin-Xin; Guo Bao-Long; Wu Xian-Xiang; He Chao-Hui; Li Pei; Guo Hong-Xia

    2017-01-01

    The fabrication process dependent effects on single event effects (SEEs) are investigated in a commercial silicon–germanium heterojunction bipolar transistor (SiGe HBT) using three-dimensional (3D) TCAD simulations. The influences of device structure and doping concentration on SEEs are discussed via analysis of current transient and charge collection induced by ions strike. The results show that the SEEs representation of current transient is different from representation of the charge collection for the same process parameters. To be specific, the area of C/S junction is the key parameter that affects charge collection of SEE. Both current transient and charge collection are dependent on the doping of collector and substrate. The base doping slightly influences transient currents of base, emitter, and collector terminals. However, the SEEs of SiGe HBT are hardly affected by the doping of epitaxial base and the content of Ge. (paper)

  16. Amorphous silicon germanium carbide photo sensitive bipolar junction transistor with a base-contact and a continuous tunable high current gain

    Energy Technology Data Exchange (ETDEWEB)

    Bablich, A., E-mail: andreas.bablich@uni-siegen.de [Department of Electrical and Computer Engineering, Institute for Microsystem Technologies, University of Siegen, Hoelderlinstrasse 3, 57076 Siegen (Germany); Merfort, C., E-mail: merfort@imt.e-technik.uni-siegen.de [Department of Electrical and Computer Engineering, Institute for Microsystem Technologies, University of Siegen, Hoelderlinstrasse 3, 57076 Siegen (Germany); Eliasz, J., E-mail: jacek.eliasz@student.uni-siegen.de [Department of Electrical and Computer Engineering, Institute for Microsystem Technologies, University of Siegen, Hoelderlinstrasse 3, 57076 Siegen (Germany); Schäfer-Eberwein, H., E-mail: heiko.schaefer@uni-siegen.de [Department of Electrical and Computer Engineering, Institute of High Frequency and Quantum Electronics, University of Siegen, Hoelderlinstrasse 3, 57076 Siegen (Germany); Haring-Bolivar, P., E-mail: peter.haring@uni-siegen.de [Department of Electrical and Computer Engineering, Institute of High Frequency and Quantum Electronics, University of Siegen, Hoelderlinstrasse 3, 57076 Siegen (Germany); Boehm, M., E-mail: markus.boehm@uni-siegen.de [Department of Electrical and Computer Engineering, Institute for Microsystem Technologies, University of Siegen, Hoelderlinstrasse 3, 57076 Siegen (Germany)

    2014-05-02

    In this paper, the design, fabrication and characterization of an amorphous silicon germanium carbide (a-SiGeC:H) photo sensitive bipolar junction transistor (PS-BJT) with three terminals are presented. Whereas the current gain of similar transistor devices presented in the past (Wu et al., 1984; Hwang et al., 1993; Nascetti and Caputo, 2002; Chang et al., 1985a,b; Wu et al, 1985; Hong et al., 1990) can only be controlled with photo induced charge generation, the n–i–δp–i–n structure developed features a contacted base to provide the opportunity to adjust the current gain optically and electrically, too. Electron microscope-, current-/voltage- and spectral measurements were performed to study the PS-BJT behavior and calculate the electrical and optical current gain. The spectral response maximum of the base–collector diode has a value of 170 mA/W applying a base–collector voltage of − 1 V and is located at 620 nm. The base–emitter diode reaches a sensitivity of 25.7 mA/W at 530 nm with a base-emitter voltage of − 3 V. The good a-Si:H transport properties are validated in a μτ-product of 4.6 × 10{sup −6} cm{sup 2} V s, which is sufficient to reach a continuous base- and photo-tunable current gain of up to − 126 at a base current of I{sub B} = + 10 nA and a collector–emitter voltage of V{sub CE} = − 3 V. The transistor obtains a maximum collector current of − 65.5 μA (V{sub CE} = − 3 V) and + 56.2 μA (V{sub CE} = + 3 V) at 10,000 lx 5300 K white-light illumination. At 3300 lx, the electrical current gain reaches a value of + 100 (V{sub CE} = + 2 V) at I{sub B} = 10 nA. With a negative base current of I{sub B} = − 10 nA the electrical gain can be adjusted between 87 (V{sub CE} = + 2 V) and − 106 (V{sub CE} = -3 V), respectively. When no base charge is applied, the transistor is “off” for V{sub CE} > − 3 V. Reducing the base current increases the electrical current gain. Operating with a voltage V{sub CE} of just ± 2 V

  17. A study on the properties of C-doped Ge8Sb2Te11 thin films during an amorphous-to-crystalline phase transition

    Science.gov (United States)

    Park, Cheol-Jin; Kong, Heon; Lee, Hyun-Yong; Yeo, Jong-Bin

    2016-04-01

    In this work, we evaluated the structural, electrical and optical properties of carbon-doped Ge8Sb2Te11 thin films. In a previous work, GeSbTe alloys were doped with different materials in an attempt to improve the thermal stability. Ge8Sb2Te11 and carbon-doped Ge8Sb2Te11 films of 250 nm in thickness were deposited on p-type Si (100) and glass substrates by using a RF magnetron reactive co-sputtering system at room temperature. The fabricated films were annealed in a furnance in the 0 ~ 400°C temperature range. The structural properties were analyzed by using X-ray diffraction (XRD), and the result showed that the carbon-doped Ge8Sb2Te11 had a face-centeredcubic (fcc) crystalline structure and an increased crystallization temperature ( T c ). An increase in the T c leads to thermal stability in the amorphous state. The optical properties were analyzed by using an UV-Vis-IR spectrophotometer, and the result showed an increase in the optical-energy band gap ( E op ) in the crystalline materials and an increase in the E op difference (Δ E op ), which is a good effect for reducing the noise in the memory device. The electrical properties were analyzed by using a 4-point probe, which showed an increase in the sheet resistance ( R s ) in the amorphous state and the crystalline state, which means a reduced programming current in the memory device.

  18. Trivalued Memory Circuit Using Metal-Oxide-Semiconductor Field-Effect Transistor Bipolar-Junction-Transistor Negative-Differential-Resistance Circuits Fabricated by Standard SiGe Process

    Science.gov (United States)

    Gan, Kwang-Jow; Tsai, Cher-Shiung; Liang, Dong-Shong; Wen, Chun-Ming; Chen, Yaw-Hwang

    2006-09-01

    A trivalued memory circuit based on two cascoded metal-oxide-semiconductor field-effect transistor bipolar-junction-transistor negative-differential-resistance (MOS-BJT-NDR) devices is investigated. The MOS-BJT-NDR device is made of MOS and BJT devices, but it can show the NDR current-voltage characteristic by suitably arranging the MOS parameters. We demonstrate a trivalued memory circuit using the two-peak MOS-BJT-NDR circuit as the driver and a resistor as the load. The MOS-BJT-NDR devices and memory circuits are fabricated by the standard 0.35 μm SiGe process.

  19. Vortex states near absolute zero in a weak-pinning amorphous Mo x Ge1-x film probed by pulsed mode-locking resonance

    Science.gov (United States)

    Sohara, N.; Ochi, A.; Murakami, E.; Ienaga, K.; Kaneko, S.; Kokubo, N.; Okuma, S.

    2017-07-01

    We have developed measurements of the mode-locking (ML) resonance with pulsed currents, which generates much less heat than the conventional one with continuous currents. Here, we present the experimental details of the pulsed ML measurement. Using this technique, we have succeeded in determining the dynamic melting field of a driven vortex lattice for a weak-pinning thick amorphous Mo x Ge1-x film down to 0.05 K. We construct an ideal vortex phase diagram in the absence of pinning near zero temperature as a function of magnetic field.

  20. Amorphous Hierarchical Porous GeOx as High-Capacity Anodes for LiIon Batteries with Very Long Cycling Life

    Energy Technology Data Exchange (ETDEWEB)

    Wang, X.L.; Han, W.-Q.; Chen, H.; Bai, J.; Tyson, T.A.; Yu, X.-Q.; Wang, X.-J.; Yang, X.-Q.

    2011-12-28

    Many researchers have focused in recent years on resolving the crucial problem of capacity fading in Li ion batteries when carbon anodes are replaced by other group-IV elements (Si, Ge, Sn) with much higher capacities. Some progress was achieved by using different nanostructures (mainly carbon coatings), with which the cycle numbers reached 100-200. However, obtaining longer stability via a simple process remains challenging. Here we demonstrate that a nanostructure of amorphous hierarchical porous GeO{sub x} whose primary particles are {approx}3.7 nm diameter has a very stable capacity of {approx}1250 mA h g{sup -1} for 600 cycles. Furthermore, we show that a full cell coupled with a Li(NiCoMn){sub 1/3}O{sub 2} cathode exhibits high performance.

  1. Photo-expansion in Ge-As-S amorphous film monitored by diital holograpic microscopy and atomic force microscopy

    Czech Academy of Sciences Publication Activity Database

    Knotek, P.; Arseva, D.; Vateva, E.; Tichý, Ladislav

    2009-01-01

    Roč. 11, č. 4 (2009), s. 391-394 ISSN 1454-4164 Institutional research plan: CEZ:AV0Z40500505 Keywords : amorphous chalcogenide films Subject RIV: CA - Inorganic Chemistry Impact factor: 0.433, year: 2009

  2. On the thickness dependence of both the optical band gap and reversible photodarkening in amorphous Ge-Se films.

    Czech Academy of Sciences Publication Activity Database

    Kutálek, P.; Tichý, Ladislav

    2016-01-01

    Roč. 619, 30 November (2016), s. 336-341 ISSN 0040-6090 Institutional support: RVO:61389013 Keywords : amorphous chalcogenides * thin films * optical band gap Subject RIV: CA - Inorganic Chemistry Impact factor: 1.879, year: 2016

  3. The phase-change kinetics of amorphous Ge2Sb2Te5 and device characteristics investigated by thin-film mechanics

    International Nuclear Information System (INIS)

    Cho, Ju-Young; Kim, Dohyung; Park, Yong-Jin; Yang, Tae-Youl; Lee, Yoo-Yong; Joo, Young-Chang

    2015-01-01

    For high switching speed and high reliability of phase-change random access memory (PcRAM), we need to identify materials that enable fast crystallization at elevated temperatures but are stable at and above room temperature. Achieving this goal requires a breakthrough in our understanding of the unique crystallization kinetics of amorphous phase change materials as a fragile glass, described as the non-Arrhenius behavior of atomic mobility. It is a highly rewarding task to unravel the unconventional crystallization kinetics and related properties, because these properties can be utilized to predict the device characteristics. This manuscript utilizes the thin-film mechanics to investigate the crystallization kinetics of amorphous Ge 2 Sb 2 Te 5 phase-change materials doped with Al, Bi, C and N, which is an effective method to analyze the structural changes in amorphous materials. Crystallization temperature, super-cooled liquid region, glass transition temperature and fragility are measured to describe the crystallization kinetics tuned by doping; characteristic fragile-to-strong transition is observed for C and N dopings due to their structural feature as an interstitial dopant. Consequently, doping effects on the phase stability and atomic mobility manifested by the crystallization temperature and the super-cooled liquid region (or 1/fragility) successfully correspond with PcRAM characteristics, i.e., reliability and switching speed, respectively

  4. Optical waveguide based on amorphous Er{sup 3+}-doped Ga-Ge-Sb-S(Se) pulsed laser deposited thin films

    Energy Technology Data Exchange (ETDEWEB)

    Nazabal, V., E-mail: virginie.nazabal@univ-rennes1.f [Sciences Chimiques de Rennes (SCR), UMR CNRS 6226, Equipe Verres et Ceramiques, Universite de Rennes 1, Rennes (France); Nemec, P. [Department of General and Inorganic Chemistry and Research Center, Faculty of Chemical Technology, University of Pardubice, Legions Sq. 565, 53210, Pardubice (Czech Republic); Jurdyc, A.M [Laboratoire de Physico-Chimie des Materiaux Luminescents (LPCML), UMR CNRS 5620, Universite Claude Bernard-Lyon 1, Villeurbanne (France); Zhang, S.; Charpentier, F. [Sciences Chimiques de Rennes (SCR), UMR CNRS 6226, Equipe Verres et Ceramiques, Universite de Rennes 1, Rennes (France); Lhermite, H. [IETR-Microelectronique, UMR CNRS 6251, Universite de Rennes 1, 35042 Rennes (France); Charrier, J. [FOTON, UMR 6082-ENSSAT, UMR CNRS 6251, Universite de Rennes 1, 35042 Rennes (France); Guin, J.P. [LARMAUR, UMR CNRS 6251, Universite de Rennes 1, 35042 Rennes (France); Moreac, A. [Institut de Physique de Rennes, UMR CNRS 6251, Universite de Rennes 1, 35042 Rennes (France); Frumar, M. [Department of General and Inorganic Chemistry and Research Center, Faculty of Chemical Technology, University of Pardubice, Legions Sq. 565, 53210, Pardubice (Czech Republic); Adam, J.-L. [Sciences Chimiques de Rennes (SCR), UMR CNRS 6226, Equipe Verres et Ceramiques, Universite de Rennes 1, Rennes (France)

    2010-06-30

    Amorphous chalcogenide films play a motivating role in the development of integrated planar optical circuits due to their potential functionality in near infrared (IR) and mid-IR spectral regions. More specifically, the photoluminescence of rare earth ions in amorphous chalcogenide films can be used in laser and amplifier devices in the IR spectral domain. The aim of the present investigation was to optimize the deposition conditions for the fabrication of undoped and Er{sup 3+} doped sulphide and selenide thin films with nominal composition Ga{sub 5}Ge{sub 20}Sb{sub 10}S(Se){sub 65} or Ga{sub 5}Ge{sub 23}Sb{sub 5}S{sub 67} by pulsed laser deposition (PLD). The study of compositional, morphological and structural characteristics of the layers was realized by scanning electron microscopy-energy dispersive spectroscopy, atomic force microscopy and Raman spectroscopy analyses, respectively. Some optical properties (transmittance, index of refraction, optical band gap, etc.) of prepared chalcogenide films and optical losses were investigated as well. The clear identification of near-IR photoluminescence of Er{sup 3+} ions was obtained for both selenide and sulphide films. The decay of the {sup 4}I{sub 13/2} {yields} {sup 4}I{sub 15/2} transition at 1.54 {mu}m in Er{sup 3+} doped Ga{sub 5}Ge{sub 20}Sb{sub 10}S{sub 65} PLD sulphide films was studied to assess the effects of film thickness, rare earth concentration and multilayer PLD deposition on their spectroscopic properties.

  5. CORRIGENDUM First principles study of crystalline and amorphous Ge2Sb2Te5 and the effects of stoichiometric defects First principles study of crystalline and amorphous Ge2Sb2Te5 and the effects of stoichiometric defects

    Science.gov (United States)

    Caravati, S.; Bernasconi, M.; Kühne, T. D.; Krack, M.; Parrinello, M.

    2010-10-01

    The distributions of coordination numbers reported in the insets of figure 7 actually refer to a bonding cutoff of 3.2 Å for all pairs of atoms. The distributions of coordination numbers referred to in the paper with bonding cutoff equal to 3.2 Å for all pairs but Sb-Te for which the bonding cutoff was set to the outer edge of the pair correlation function of c-GST (3.4 Å at 300 K) are given below for the three compounds. figure 1 Figure 7. Distribution of coordination numbers of different species obtained by integration of the partial pair correlation functions for (from left to right) Ge2Sb2Te5, Ge2Sb1.8Te5 and Ge2.2Sb2Te5.

  6. The crystal structure and electronic properties of a new metastable non-stoichiometric BaAl{sub 4}-type compound crystallized from amorphous La{sub 6}Ni{sub 34}Ge{sub 60} alloy

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, Masashi [Institute for Materials Research, Tohoku University, Sendai, Katahira 980-8577 (Japan); Suzuki, Shoichiro [Institute for Materials Research, Tohoku University, Sendai, Katahira 980-8577 (Japan); Ohsuna, Tetsu [Institute for Materials Research, Tohoku University, Sendai, Katahira 980-8577 (Japan); Matsubara, Eiichiro [Institute for Materials Research, Tohoku University, Sendai, Katahira 980-8577 (Japan); Endo, Satoshi [Center for Low Temperature Science, Tohoku University, Sendai, Katahira 980-8577 (Japan); Inoue, Akihisa [Institute for Materials Research, Tohoku University, Sendai, Katahira 980-8577 (Japan)

    2004-11-17

    A new metastable La-Ge-Ni ternary BaAl{sub 4}-type (ThCr{sub 2}Si{sub 2}-type) compound, of which the space group is I4/mmm is synthesized. It is obtained by a polymorphic transformation from an La{sub 6}Ni{sub 34}Ge{sub 60} amorphous alloy on crystallizing. The formula of the compound is (La{sub 0.3}Ge{sub 0.7})(Ni{sub 0.85}Ge{sub 0.15}){sub 2}Ge{sub 2}. This indicates that it is highly non-stoichiometric compared to the stoichiometric LaNi{sub 2}Ge{sub 2}. It is found that the c-axis lattice parameter of this compound is much longer than that of LaNi{sub 2}Ge{sub 2}. It should be noted that the longer c-axis unit cell parameter is attributable only to the longer interlayer distance between Ge site and Ni site layers. The temperature dependences of electrical resistivity and thermoelectric power of the (La{sub 0.3}Ge{sub 0.7})(Ni{sub 0.85}Ge{sub 0.15}){sub 2}Ge{sub 2} compound and La{sub 6}Ni{sub 34}Ge{sub 60} amorphous alloy are also clarified. The comparison of these electronic properties between the two materials indicates that sp-electrons mainly contribute to the density of states around the Fermi level of this compound.

  7. Structural investigation of the amorphous/crystalline interface by means of quantitative high-resolution transmission electron microscopy on the systems a-Si/c-Si and a-Ge/c-Si; Strukturelle Untersuchung der amorph/kristallinen Grenzflaeche mittels quantitativer hochaufloesender Transmissionselektronenmikroskopie an den Systemen a-Si/c-Si und a-Ge/c-Si

    Energy Technology Data Exchange (ETDEWEB)

    Thiel, K.

    2006-11-02

    In this Thesis the interfaces between covalently bonded crystalline and amorphous materials were studied with regard to the induced ordering in the amorphous material in the interfacial region by means of high-resolution transmission electron microscopy (HREM). The interface between amorphous germanium and crystalline silicon and the interface between amorphous and crystalline silicon served as material system. In order to quantify the influence of the crystalline order on the amorphous material, the HREM images were periodically averaged along the interface. The intensity components, which are correlated with the period of the lattice image, could thus be separated from the statistical intensity fluctuations, which are characteristic for images of amorphous materials. Since amorphous materials can only be described meaningful by statistical distribution functions, for the induced order a three-dimensional distribution function {rho}{sub 3D}(r) was taken as a basis, which describes the probability to find an atom in the amorphous material, if r=0 is the position of an atom in the crystal. Its two-dimensional projection, {rho}, can be determined using iterative image matching techniques on averaged experimental and simulated interface images. For the analyzed material systems {rho} exhibits lateral ordering as well as a pronounced layering in the vicinity of the interface. In the case of the a-Si/c-Si sample the mean orientation of bonds was 70.5 , as is in the case of the undistorted diamond lattice, while for the a-Ge/c-Si sample 65 resulted. The standard deviation for the distribution of the deviations from the mean bond angle yields for the a-Ge/c-Si sample in the first atomic layer a value of 11.3 and for the a-Si/c-Si sample 1.9 . These results suggest the conclusion, that the differences in these values are to be interpreted as the reaction of the amorphous material to the volume misfit. Although for both material systems 1.4 nm was calculated for the width

  8. ac conductivity and dielectric properties of amorphous Se{sub 80}Te{sub 20-x}Ge{sub x} chalcogenide glass film compositions

    Energy Technology Data Exchange (ETDEWEB)

    Hegab, N.A. [Physics Department, Faculty of Education, Ain Shams University, Cairo (Egypt)], E-mail: abir_net_2005@hotmail.com; Afifi, M.A.; Atyia, H.E.; Farid, A.S. [Physics Department, Faculty of Education, Ain Shams University, Cairo (Egypt)

    2009-05-27

    Thin films of the prepared Se{sub 80}Te{sub 20-x}Ge{sub x} (x = 5, 7 and 10 at.%) were prepared by thermal evaporation technique. X-ray diffraction patterns showed that the films were in amorphous state. The ac conductivity and dielectric properties of the investigated film compositions were studied in the frequency range 0.1-100 kHz and in temperature range (303-373 K). The experimental results indicated that the ac conductivity and the dielectric properties depended on the temperature and frequency. The ac conductivity is found to obey the {omega}{sup s} law, in accordance with the hopping model, s is found to be temperature dependent (s < 1) and its value goes down as the temperature is increased. The temperature dependence of ac conductivity can be reasonably interpreted in terms of the correlated barrier hopping (CBH) model. Values of dielectric constant {epsilon}{sub 1} and dielectric loss {epsilon}{sub 2} were found to decrease with frequency and increase with temperature. The maximum barrier height W{sub m}, calculated from dielectric measurements according to Guintini equation, agrees with that proposed by the theory of hopping over potential barrier as suggested by Elliott in case of chalcogenide glasses. The density of localized states was estimated for the studied film compositions. The variation of the studied properties with Ge content was also investigated.

  9. Threshold switching in the amorphous semiconductor As/sub 15/Te/sub 70/Ge/sub 15/ and in the organic semiconductor melanin

    Energy Technology Data Exchange (ETDEWEB)

    Culp, C.H. III

    1976-06-01

    The threshold switching properties of the amorphous semiconductor As/sub 15/Te/sub 70/Ge/sub 15/ and the organic semiconductor melanin have been examined with threshold switching experiments. Measurements of delay time, energy and average resistance as functions of applied voltage were made by a computer controlled data acquisition system. These measurements were made on As/sub 15/Te/sub 70/Ge/sub 15/ at 243, 273 and 298/sup 0/K. A time dependent electrothermal model was solved numerically. The material parameters that were measured for this model are activation energy, sample thickness, conductivity at T equal to infinity, and area of the electrodes. With these measured parameters the calculation was compared to the experimental values of delay time, energy, and average resistance as functions of applied voltage. The measured data and the calculations are in good agreement. Melanin was prepared from a lyophilized powder into a hydrated pellet. The melanin pellets were studied at 298, 190, and 77/sup 0/K with a double pulse apparatus. Time dependent current versus voltage characteristics were also measured. Melanin exhibits threshold switching at low electric fields (about 10/sup 2/ V/cm). The results from the melanin experiments show that threshold switching in melanin can be explained by a thermal runaway model. A pseudo-memory effect was also found in melanin.

  10. High Power SiGe X-Band (8-10 GHz) Heterojunction Bipolar Transistors and Amplifiers

    Science.gov (United States)

    Ma, Zhenqiang; Jiang, Ningyue; Ponchak, George E.; Alterovitz, Samuel A.

    2005-01-01

    Limited by increased parasitics and thermal effects as the device size becomes large, current commercial SiGe power HBTs are difficult to operate at X-band (8-12 GHz) with adequate power added efficiencies at high power levels. We found that, by changing the heterostructure and doping profile of SiGe HBTs, their power gain can be significantly improved without resorting to substantial lateral scaling. Furthermore, employing a common-base configuration with proper doping profile instead of a common-emitter configuration improves the power gain characteristics of SiGe HBTs, which thus permits these devices to be efficiently operated at X-band. In this paper, we report the results of SiGe power HBTs and MMIC power amplifiers operating at 8-10 GHz. At 10 GHz, 22.5 dBm (178 mW) RF output power with concurrent gain of 7.32 dB is measured at the peak power-added efficiency of 20.0% and the maximum RF output power of 24.0 dBm (250 mW) is achieved from a 20 emitter finger SiGe power HBT. Demonstration of single-stage X-band medium-power linear MMIC power amplifier is also realized at 8 GHz. Employing a 10-emitter finger SiGe HBT and on-chip input and output matching passive components, a linear gain of 9.7 dB, a maximum output power of 23.4 dBm and peak power added efficiency of 16% is achieved from the power amplifier. The MMIC exhibits very low distortion with third order intermodulation (IM) suppression C/I of -13 dBc at output power of 21.2 dBm and over 20dBm third order output intercept point (OIP3).

  11. Power SiGe Heterojunction Bipolar Transistors (HBTs) Fabricated by Fully Self-Aligned Double Mesa Technology

    Science.gov (United States)

    Lu, Liang-Hung; Mohammadi, Saeed; Ma, Zhen-Qiang; Ponchak, George E.; Alterovitz, Samuel A.; Strohm, Karl M.; Luy, Johann-Friedrich; Downey, Alan (Technical Monitor)

    2001-01-01

    Multifinger SiGe HBTs have been fabricated using a novel fully self-aligned double-mesa technology. With the novel process technology, a common-emitter 2x2x30 sq micrometer device exhibits high maximum oscillating frequency (f(sub max)) and cut-off frequency (f(sub T)) of 78 and 37 GHz, respectively. In class-A operation, a multifinger device with l0x2x30 sq micrometer emitter is expected to provide an output power of 25.6 dBm with a gain of 10 dB and a maximum power added efficiency (PAE) of 30.33% at 8 GHz.

  12. On the photo-induced shift of the optical gap in amorphous Ge6As43S35Se16 film

    Czech Academy of Sciences Publication Activity Database

    Kincl, Miloslav; Tasseva, J.; Petkov, K.; Knotek, P.; Tichý, Ladislav

    2009-01-01

    Roč. 11, č. 4 (2009), s. 395-398 ISSN 1454-4164 Institutional research plan: CEZ:AV0Z40500505 Keywords : amorphous chalcogenide film Subject RIV: CA - Inorganic Chemistry Impact factor: 0.433, year: 2009

  13. Amorphous-to-crystalline transition in Ge8Sb(2-x)BixTe11 phase-change materials for data recording

    Czech Academy of Sciences Publication Activity Database

    Svoboda, R.; Karabyn, V.; Málek, J.; Frumar, M.; Beneš, L.; Vlček, Milan

    2016-01-01

    Roč. 674, July (2016), s. 63-72 ISSN 0925-8388 Institutional support: RVO:61389013 Keywords : amorphous materials * calorimetry * data strorage materials Subject RIV: CA - Inorganic Chemistry Impact factor: 3.133, year: 2016

  14. Green, red and near-infrared photon up-conversion in Ga-Ge-Sb-S:Er.sup.3+./sup. amorphous chalcogenides

    Czech Academy of Sciences Publication Activity Database

    Střižík, L.; Zhang, J.; Wágner, T.; Oswald, Jiří; Kohoutek, T.; Walsh, B. M.; Přikryl, J.; Svoboda, R.; Liu, C.; Frumarová, Božena; Frumar, M.; Pavlista, M.; Park, W.J.; Heo, J.

    2014-01-01

    Roč. 147, Mar (2014), s. 209-215 ISSN 0022-2313 R&D Projects: GA ČR GA203/09/0827; GA MŠk(CZ) LH11101 Institutional support: RVO:68378271 ; RVO:61389013 Keywords : Er * Ga-Ge-Sb-S * chalcogenide glasses * up-conversion * Judd-Ofelt analysis Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.719, year: 2014

  15. Bipolar Disorder

    Science.gov (United States)

    Bipolar disorder is a serious mental illness. People who have it go through unusual mood changes. They go ... The down feeling is depression. The causes of bipolar disorder aren't always clear. It runs in families. ...

  16. Amorphous magnetism

    International Nuclear Information System (INIS)

    Rechenberg, H.R.

    1984-01-01

    The consequences of disorder on magnetic properties of solids are examined. In this context the word 'disorder' is not synonimous of structural amorphicity; chemical disorder can be achieved e.g. by randomly diffusing magnetic atoms on a nonmagnetic crystalline lattice. The name Amorphous Magnetism must be taken in a broad sense. (Author) [pt

  17. Amorphous nanophotonics

    CERN Document Server

    Scharf, Toralf

    2013-01-01

    This book represents the first comprehensive overview over amorphous nano-optical and nano-photonic systems. Nanophotonics is a burgeoning branch of optics that enables many applications by steering the mould of light on length scales smaller than the wavelength with devoted nanostructures. Amorphous nanophotonics exploits self-organization mechanisms based on bottom-up approaches to fabricate nanooptical systems. The resulting structures presented in the book are characterized by a deterministic unit cell with tailored geometries; but their spatial arrangement is not controlled. Instead of periodic, the structures appear either amorphous or random. The aim of this book is to discuss all aspects related to observable effects in amorphous nanophotonic material and aspects related to their design, fabrication, characterization and integration into applications. The book has an interdisciplinary nature with contributions from scientists in physics, chemistry and materials sciences and sheds light on the topic fr...

  18. Bipolar disorder

    Science.gov (United States)

    ... of pleasure in activities once enjoyed Loss of self-esteem Thoughts of death or suicide Trouble getting to ... other. This is called rapid cycling. Exams and Tests To diagnose bipolar disorder, the provider may do ...

  19. Bipolar disorder

    Directory of Open Access Journals (Sweden)

    F Colin

    2013-08-01

    Full Text Available Bipolar disorder (BD presents in different phases over time and is oftencomplicated by comorbid conditions such as substance-use disordersand anxiety disorders. Treatment usually involves pharmacotherapywith combinations of different classes of medications and frequentmedication revisions.

  20. Pressure-induced reversible amorphization and an amorphous-amorphous transition in Ge₂Sb₂Te₅ phase-change memory material.

    Science.gov (United States)

    Sun, Zhimei; Zhou, Jian; Pan, Yuanchun; Song, Zhitang; Mao, Ho-Kwang; Ahuja, Rajeev

    2011-06-28

    Ge(2)Sb(2)Te(5) (GST) is a technologically very important phase-change material that is used in digital versatile disks-random access memory and is currently studied for the use in phase-change random access memory devices. This type of data storage is achieved by the fast reversible phase transition between amorphous and crystalline GST upon heat pulse. Here we report pressure-induced reversible crystalline-amorphous and polymorphic amorphous transitions in NaCl structured GST by ab initio molecular dynamics calculations. We have showed that the onset amorphization of GST starts at approximately 18 GPa and the system become completely random at approximately 22 GPa. This amorphous state has a cubic framework (c-amorphous) of sixfold coordinations. With further increasing pressure, the c-amorphous transforms to a high-density amorphous structure with trigonal framework (t-amorphous) and an average coordination number of eight. The pressure-induced amorphization is investigated to be due to large displacements of Te atoms for which weak Te-Te bonds exist or vacancies are nearby. Upon decompressing to ambient conditions, the original cubic crystalline structure is restored for c-amorphous, whereas t-amorphous transforms to another amorphous phase that is similar to the melt-quenched amorphous GST.

  1. Bipolar Disorder (For Teens)

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español Bipolar Disorder KidsHealth / For Teens / Bipolar Disorder What's in this ... Disorder Print en español Trastorno bipolar What Is Bipolar Disorder? Bipolar disorders are one of several medical conditions ...

  2. Neutrality in bipolar structures

    DEFF Research Database (Denmark)

    Montero, Javier; Rodríguez, J. Tinguaro; Franco, Camilo

    2014-01-01

    In this paper, we want to stress that bipolar knowledge representation naturally allows a family of middle states which define as a consequence different kinds of bipolar structures. These bipolar structures are deeply related to the three types of bipolarity introduced by Dubois and Prade, but our...... approach offers a systematic explanation of how such bipolar structures appear and can be identified....

  3. Phase transformations of amorphous semiconductor alloys under high pressures

    CERN Document Server

    Antonov, V E; Fedotov, V K; Harkunov, A I; Ponyatovsky, E G

    2002-01-01

    The paper reviews the results of experimental studies and thermodynamical modelling of metastable T-P diagrams of initially amorphous GaSb-Ge and Zn-Sb alloys which provide a new insight into the problem of pressure-induced amorphization.

  4. What is Bipolar Disorder?

    Science.gov (United States)

    ... affect friends and family? For More Information Share Bipolar Disorder Download PDF Download ePub Order a free hardcopy ... brochure will give you more information. What is bipolar disorder? Bipolar disorder is a serious brain illness. It ...

  5. Amorphous germanium as an electron or hole blocking contact on high-purity germanium detectors

    International Nuclear Information System (INIS)

    Hansen, W.L.; Haller, E.E.

    1976-10-01

    Experiments were performed in an attempt to make thin n + contacts on high-purity germanium by the solid phase/sup 1)/ epitaxial regrowth of arsenic doped amorphous germanium. After cleaning the crystal surface with argon sputtering and trying many combinations of layers, it was not found possible to induce recrystallization below 400 0 C. However, it was found that simple thermally evaporated amorphous Ge made fairly good electron or hole blocking contacts. Excellent spectrometers have been made with amorphous Ge replacing the n + contact. As presently produced, the amorphous Ge contact diodes show a large variation in high-voltage leakage current

  6. Transtorno bipolar

    Directory of Open Access Journals (Sweden)

    Alda Martin

    1999-01-01

    Full Text Available Os resultados de estudos de famílias sugerem que o transtorno bipolar tenha uma base genética. Essa hipótese foi reforçada em estudos de adoção e de gêmeos. A herança do transtorno bipolar é complexa, envolve vários genes, além de apresentar heterogeneidade e interação entre fatores genéticos e não-genéticos. Achados, que já foram replicados, já implicaram os cromossomos 4, 12, 18 e 21, entre outros, na busca por genes de suscetibilidade. Os resultados mais promissores foram obtidos através de estudos de ligação. Por outro lado, os estudos de associação geraram dados interessantes, mas ainda vagos. Os estudos de populações de pacientes homogêneos e a melhor definição do fenótipo deverão contribuir para avanços futuros. A identificação dos genes relacionados ao transtorno bipolar irá permitir o melhor entendimento e tratamento dessa doença.

  7. Bipolar disorder: an overview

    African Journals Online (AJOL)

    which is the reason that up to 69% of patients with BD are misdiagnosed.1 Bipolar ... Cyclothymic disorder. • Substance/medication induced bipolar and related disorder. • Bipolar and related disorder due to another medical condition ... patients. Keywords: bipolar disorder, mania, depression, pharmacological management.

  8. Magnetic anisotropy of (Ge,Mn) nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Jain, A; Jamet, M; Barski, A; Devillers, T; Yu, I-S; Porret, C; Gambarelli, S; Maurel, V; Desfonds, G; Jacquot, J F, E-mail: abhinav.jain@cea.fr [Institut Nanosciences et Cryogenie, CEA-UJF, F-38054, Grenoble (France)

    2011-04-01

    We present a correlation between structural and magnetic properties of different (Ge,Mn) nanostructures grown on Ge(001) and Ge(111) substrates. Thin films of Ge{sub 1-x}Mn{sub x} were grown by low temperature molecular beam epitaxy to favor the out-of-equilibrium growth. Depending on the growth conditions crystalline or amorphous (Ge,Mn) nanocolumns have been observed on Ge(001) substrates. The magnetic properties were probed by superconducting quantum interference device (SQUID), vibrating sample magnetometer (VSM) and electron paramagnetic resonance (EPR). With the help of these complementary techniques (SQUID and EPR), magnetic anisotropy in these nanostructures has been investigated and different anisotropy constants were calculated.

  9. Bipolar Items

    Directory of Open Access Journals (Sweden)

    Nishiguchi Sumiyo

    2016-12-01

    Full Text Available This article asserts that the Japanese wide-scope mo ‘even’ in simple sentences are bipolar items (BPIs antilicensed or forbidden by negation and licensed in a non-monotonic (NM environment. BPIs share the features of negative polarity items (NPIs as well as positive polarity items (PPIs. The Dutch ooit ‘ever’, the Serbo-Croatian i-series ‘and/even’, and the Hungarian is-series ‘and/even’ are antilicensed by clausemate negation and licensed by extraclausal negation (van der Wouden, 1997; Progovac, 1994; Szabolcsi, 2002 or non-monotonic negative (and positive, for Serbo-Croatian emotive predicates. Adding an NPI rescues BPIs in uncomfortable clausemate negation.

  10. Types of Bipolar Disorder

    Science.gov (United States)

    ... many people have bipolar disorder along with another illness such as anxiety disorder, substance abuse, or an eating disorder. People with ... are sometimes misdiagnosed with schizophrenia. Anxiety and ADHD: ... such as bipolar disorder. Risk Factors Scientists are ...

  11. Cytokines in bipolar disorder

    DEFF Research Database (Denmark)

    Munkholm, Klaus; Vinberg, Maj; Vedel Kessing, Lars

    2012-01-01

    to affective state. METHODS: We conducted a systemtic review of studies measuring endogenous cytokine concentrations in patients with bipolar disorder and a meta-analysis, reporting results according to the PRISMA statement. RESULTS: Thirteen studies were included, comprising 556 bipolar disorder patients......BACKGROUND: Current research and hypothesis regarding the pathophysiology of bipolar disorder suggests the involvement of immune system dysfunction that is possibly related to disease activity. Our objective was to systematically review evidence of cytokine alterations in bipolar disorder according...

  12. Soft chemistry routes to GeS2 nanoparticles

    Science.gov (United States)

    Courthéoux, Laurence; Mathiaud, Romain; Ribes, Michel; Pradel, Annie

    2018-04-01

    Spherical GeS2 particles are prepared by a low temperature liquid route with TEOG as germanium precursor and either H2S or thioacetamide (TAA) as sulfur precursors. The size and agglomeration of the particles change depending upon the temperature and nature of the solvent. Most synthesis lead to preparing amorphous GeS2. When the reaction kinetic is slowed down by using TAA at 25 °C, the obtained GeS2 product presents a larger order in the range of few Å as proven by Raman spectroscopy, even though it is still an amorphous compound as suggested by X-Ray diffraction and TEM experiments.

  13. Psychotic and Bipolar Disorders: Bipolar Disorder.

    Science.gov (United States)

    Holder, Sarah D

    2017-04-01

    Bipolar disorder is a severe chronic mental illness that affects a large number of individuals. This disorder is separated into two major types, bipolar I disorder, with mania and typically recurrent depression, and bipolar II disorder, with recurrent major depression and hypomania. Patients with bipolar disorder spend the majority of time experiencing depression, and this typically is the presenting symptom. Because outcomes are improved with earlier diagnosis and treatment, physicians should maintain a high index of suspicion for bipolar disorder. The most effective long-term treatments are lithium and valproic acid, although other drugs also are used. In addition to referral to a mental health subspecialist for initiation and management of drug treatment, patients with bipolar disorder should be provided with resources for psychotherapy. Several comorbidities commonly associated with bipolar disorder include other mental disorders, substance use disorders, migraine headaches, chronic pain, stroke, metabolic syndrome, and cardiovascular disease. Family physicians who care for patients with bipolar disorder should focus their efforts on prevention and management of comorbidities. These patients should be assessed continually for risk of suicide because they are at high risk and their suicide attempts tend to be successful. Written permission from the American Academy of Family Physicians is required for reproduction of this material in whole or in part in any form or medium.

  14. Effect of Ge Content on the Formation of Ge Nanoclusters in Magnetron-Sputtered GeZrOx-Based Structures.

    Science.gov (United States)

    Khomenkova, L; Lehninger, D; Kondratenko, O; Ponomaryov, S; Gudymenko, O; Tsybrii, Z; Yukhymchuk, V; Kladko, V; von Borany, J; Heitmann, J

    2017-12-01

    Ge-rich ZrO 2 films, fabricated by confocal RF magnetron sputtering of pure Ge and ZrO 2 targets in Ar plasma, were studied by multi-angle laser ellipsometry, Raman scattering, Auger electron spectroscopy, Fourier transform infrared spectroscopy, and X-ray diffraction for varied deposition conditions and annealing treatments. It was found that as-deposited films are homogeneous for all Ge contents, thermal treatment stimulated a phase separation and a formation of crystalline Ge and ZrO 2 . The "start point" of this process is in the range of 640-700 °C depending on the Ge content. The higher the Ge content, the lower is the temperature necessary for phase separation, nucleation of Ge nanoclusters, and crystallization. Along with this, the crystallization temperature of the tetragonal ZrO 2 exceeds that of the Ge phase, which results in the formation of Ge crystallites in an amorphous ZrO 2 matrix. The mechanism of phase separation is discussed in detail.

  15. Nutrition and Bipolar Depression.

    Science.gov (United States)

    Beyer, John L; Payne, Martha E

    2016-03-01

    As with physical conditions, bipolar disorder is likely to be impacted by diet and nutrition. Patients with bipolar disorder have been noted to have relatively unhealthy diets, which may in part be the reason they also have an elevated risk of metabolic syndrome and obesity. An improvement in the quality of the diet should improve a bipolar patient's overall health risk profile, but it may also improve their psychiatric outcomes. New insights into biological dysfunctions that may be present in bipolar disorder have presented new theoretic frameworks for understanding the relationship between diet and bipolar disorder. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Bipolar Treatment: Are Bipolar I and Bipolar II Treated Differently?

    Science.gov (United States)

    ... management strategies. In addition to medications and other types of treatment, successful management of your bipolar disorder includes living a healthy lifestyle, such as getting enough sleep, eating a healthy diet and being physically active. ...

  17. Oxide bipolar electronics: materials, devices and circuits

    Science.gov (United States)

    Grundmann, Marius; Klüpfel, Fabian; Karsthof, Robert; Schlupp, Peter; Schein, Friedrich-Leonhard; Splith, Daniel; Yang, Chang; Bitter, Sofie; von Wenckstern, Holger

    2016-06-01

    We present the history of, and the latest progress in, the field of bipolar oxide thin film devices. As such we consider primarily pn-junctions in which at least one of the materials is a metal oxide semiconductor. A wide range of n-type and p-type oxides has been explored for the formation of such bipolar diodes. Since most oxide semiconductors are unipolar, challenges and opportunities exist with regard to the formation of heterojunction diodes and band lineups. Recently, various approaches have led to devices with high rectification, namely p-type ZnCo2O4 and NiO on n-type ZnO and amorphous zinc-tin-oxide. Subsequent bipolar devices and applications such as photodetectors, solar cells, junction field-effect transistors and integrated circuits like inverters and ring oscillators are discussed. The tremendous progress shows that bipolar oxide electronics has evolved from the exploration of various materials and heterostructures to the demonstration of functioning integrated circuits. Therefore a viable, facile and high performance technology is ready for further exploitation and performance optimization.

  18. Bipolar soft connected, bipolar soft disconnected and bipolar soft compact spaces

    Directory of Open Access Journals (Sweden)

    Muhammad Shabir

    2017-06-01

    Full Text Available Bipolar soft topological spaces are mathematical expressions to estimate interpretation of data frameworks. Bipolar soft theory considers the core features of data granules. Bipolarity is important to distinguish between positive information which is guaranteed to be possible and negative information which is forbidden or surely false. Connectedness and compactness are the most important fundamental topological properties. These properties highlight the main features of topological spaces and distinguish one topology from another. Taking this into account, we explore the bipolar soft connectedness, bipolar soft disconnectedness and bipolar soft compactness properties for bipolar soft topological spaces. Moreover, we introduce the notion of bipolar soft disjoint sets, bipolar soft separation, and bipolar soft hereditary property and study on bipolar soft connected and disconnected spaces. By giving the detailed picture of bipolar soft connected and disconnected spaces we investigate bipolar soft compact spaces and derive some results related to this concept.

  19. Density functional simulations of Sb-rich GeSbTe phase change alloys

    Science.gov (United States)

    Gabardi, S.; Caravati, S.; Bernasconi, M.; Parrinello, M.

    2012-09-01

    We generated models of the amorphous phase of Sb-rich GeSbTe phase change alloys by quenching from the melt within density functional molecular dynamics. We considered the two compositions Ge1Sb1Te1 and Ge2Sb4Te5. Comparison with previous results on the most studied Ge2Sb2Te5 allowed us to draw some conclusions on the dependence of the structural properties of the amorphous phase on the alloy composition. Vibrational and electronic properties were also scrutinized. Phonons at high frequencies above 200 cm-1 are localized in tetrahedra around Ge atoms in Sb-rich compounds as well as in Ge2Sb2Te5. All compounds are semiconducting in the amorphous phase, with a band gap in the range 0.7-1.0 eV.

  20. Enhanced formation of Ge nanocrystals in Ge : SiO2 layers by swift heavy ions

    International Nuclear Information System (INIS)

    Antonova, I V; Volodin, V A; Marin, D M; Skuratov, V A; Smagulova, S A; Janse van Vuuren, A; Neethling, J; Jedrzejewski, J; Balberg, I

    2012-01-01

    In this paper we report the ability of swift heavy Xe ions with an energy of 480 MeV and a fluence of 10 12 cm -2 to enhance the formation of Ge nanocrystals within SiO 2 layers with variable Ge contents. These Ge-SiO 2 films were fabricated by the co-sputtering of Ge and quartz sources which followed various annealing procedures. In particular, we found that the irradiation of the Ge : SiO 2 films with subsequent annealing at 500 °C leads to the formation of a high concentration of nanocrystals (NCs) with a size of 2-5 nm, whereas without irradiation only amorphous inclusions were observed. This effect, as evidenced by Raman spectra, is enhanced by pre-irradiation at 550 °C and post-irradiation annealing at 600 °C, which also leads to the observation of room temperature visible photoluminescence. (paper)

  1. Phase transitions in Ge-Sb phase change materials

    International Nuclear Information System (INIS)

    Raoux, Simone; Virwani, Kumar; Cabral, Cyril Jr.; Krusin-Elbaum, Lia; Jordan-Sweet, Jean L.; Hitzbleck, Martina; Salinga, Martin; Madan, Anita; Pinto, Teresa L.

    2009-01-01

    Thin films of the phase change material Ge-Sb with Ge concentrations between 7.3 and 81.1 at. % were deposited by cosputtering from elemental targets. Their crystallization behavior was studied using time-resolved x-ray diffraction, Auger electron spectroscopy, differential scanning calorimetry, x-ray reflectivity, profilometry, optical reflectivity, and resistivity versus temperature measurements. It was found that the crystallization temperature increases with Ge content. Calculations of the glass transition temperature (which is a lower limit for the crystallization temperature T x ) also show an increase with Ge concentration closely tracking the measured values of T x . For low Ge content samples, Sb x-ray diffraction peaks occurred during a heating ramp at lower temperature than Ge diffraction peaks. The appearance of Ge peaks is related to Ge precipitation and agglomeration. For Ge concentrations of 59.3 at. % and higher, Sb and Ge peaks occurred at the same temperature. Upon crystallization, film mass density and optical reflectivity increase as well as electrical contrast (ratio of resistivity in amorphous phase to crystalline phase) all showed a maximum for the eutectic alloy (14.5 at. % Ge). For the alloy with 59.3 at. % Ge there was very little change in any of these parameters, while the alloy with 81.1 at. % Ge behaved opposite to a typical phase change alloy and showed reduced mass density and reflectivity and increased resistivity

  2. Substitutionality of Ge atoms in ion implanted AlSb

    International Nuclear Information System (INIS)

    Yu, K.M.; Moll, A.J.; Chan, N.; Walukiewicz, W.; Becla, P.

    1995-01-01

    The substitution of Ge atoms into ion implanted AlSb is investigated by extended x-ray absorption fine structure spectroscopy. Our results reveal that in the as-implanted material, the implanted Ge atoms are equally distributed between two specific sites, one surrounded by Al atoms and the other surrounded by Sb atoms. After annealing at 750 degree C for 5 s, the coordination number of the Ge atoms increases from ∼3 to ∼4 indicating solid phase regrowth of the implantation induced amorphous surface layer. Moreover, in the annealed AlSb, the substitution of Ge atoms into the Al sublattice dominates with an estimated Ge Al :[Ge Sb ]∼0.8:0.2. These results suggest that Ge atoms act preferentially as donor species in AlSb

  3. An Investigation of ELDRS in Different SiGe Processes

    Science.gov (United States)

    Li, Pei; He, Chaohui; Guo, Hongxia; Guo, Qi; Zhang, Jinxin; Liu, Mohan

    2017-05-01

    Enhanced low dose rate sensitivity (ELDRS) in different process Silicon-Germanium heterojunction bipolar transistors (SiGe HBTs) is investigated. Low and high dose rate irradiations are performed to evaluate the ELDRS of SiGe HBTs manufactured by Tsinghua University (THU). THU SiGe HBTs experience significantly low dose rate sensitivity than that of IBM 8HP SiGe HBTs and behave a “true” dose rate effect. TCAD models were used to explicate the microcosmic structure in THU and IBM 8HP SiGe HBTs. Comparison and discussion show that different SiGe processes may involve different HBT structures and device designs which are the critical influence of ELDRS effect. The different responses of ELDRS should be first attributed to the device structure and design in nature, particularly the geometry of emitter-base junction and the isolation structure.

  4. Amorphous iron (II) carbonate

    DEFF Research Database (Denmark)

    Sel, Ozlem; Radha, A.V.; Dideriksen, Knud

    2012-01-01

    Abstract The synthesis, characterization and crystallization energetics of amorphous iron (II) carbonate (AFC) are reported. AFC may form as a precursor for siderite (FeCO3). The enthalpy of crystallization (DHcrys) of AFC is similar to that of amorphous magnesium carbonate (AMC) and more...

  5. Bipolar Disorder - Multiple Languages

    Science.gov (United States)

    ... MP3 Bipolar Disorder (An Introduction) - English MP4 Bipolar Disorder (An Introduction) - español (Spanish) MP4 Healthy Roads Media Characters not displaying correctly on this page? See language display issues . Return to the MedlinePlus Health Information ...

  6. Magnetic bipolar transistor

    OpenAIRE

    Fabian, Jaroslav; Zutic, Igor; Sarma, S. Das

    2003-01-01

    A magnetic bipolar transistor is a bipolar junction transistor with one or more magnetic regions, and/or with an externally injected nonequilibrium (source) spin. It is shown that electrical spin injection through the transistor is possible in the forward active regime. It is predicted that the current amplification of the transistor can be tuned by spin.

  7. Hydrogen in amorphous silicon

    International Nuclear Information System (INIS)

    Peercy, P.S.

    1980-01-01

    The structural aspects of amorphous silicon and the role of hydrogen in this structure are reviewed with emphasis on ion implantation studies. In amorphous silicon produced by Si ion implantation of crystalline silicon, the material reconstructs into a metastable amorphous structure which has optical and electrical properties qualitatively similar to the corresponding properties in high-purity evaporated amorphous silicon. Hydrogen studies further indicate that these structures will accomodate less than or equal to 5 at.% hydrogen and this hydrogen is bonded predominantly in a monohydride (SiH 1 ) site. Larger hydrogen concentrations than this can be achieved under certain conditions, but the excess hydrogen may be attributed to defects and voids in the material. Similarly, glow discharge or sputter deposited amorphous silicon has more desirable electrical and optical properties when the material is prepared with low hydrogen concentration and monohydride bonding. Results of structural studies and hydrogen incorporation in amorphous silicon were discussed relative to the different models proposed for amorphous silicon

  8. Properties of Bipolar Fuzzy Hypergraphs

    OpenAIRE

    Akram, M.; Dudek, W. A.; Sarwar, S.

    2013-01-01

    In this article, we apply the concept of bipolar fuzzy sets to hypergraphs and investigate some properties of bipolar fuzzy hypergraphs. We introduce the notion of $A-$ tempered bipolar fuzzy hypergraphs and present some of their properties. We also present application examples of bipolar fuzzy hypergraphs.

  9. Physics of amorphous metals

    CERN Document Server

    Kovalenko, Nikolai P; Krey, Uwe

    2008-01-01

    The discovery of bulk metallic glasses has led to a large increase in the industrial importance of amorphous metals, and this is expected to continue. This book is the first to describe the theoretical physics of amorphous metals, including the important theoretical development of the last 20 years.The renowned authors stress the universal aspects in their description of the phonon or magnon low-energy excitations in the amorphous metals, e.g. concerning the remarkable consequences of the properties of these excitations for the thermodynamics at low and intermediate temperatures. Tunneling

  10. Amorphization within the tablet

    DEFF Research Database (Denmark)

    Doreth, Maria; Hussein, Murtadha Abdul; Priemel, Petra A.

    2017-01-01

    , the feasibility of microwave irradiation to prepare amorphous solid dispersions (glass solutions) in situ was investigated. Indomethacin (IND) and polyvinylpyrrolidone K12 (PVP) were tableted at a 1:2 (w/w) ratio. In order to study the influence of moisture content and energy input on the degree of amorphization......, tablet formulations were stored at different relative humidity (32, 43 and 54% RH) and subsequently microwaved using nine different power-time combinations up to a maximum energy input of 90 kJ. XRPD results showed that up to 80% (w/w) of IND could be amorphized within the tablet. mDSC measurements...

  11. Electronic transport in amorphous phase-change materials

    International Nuclear Information System (INIS)

    Luckas, Jennifer Maria

    2012-01-01

    Phase change materials combine a pronounced contrast in resistivity and reflectivity between their disordered amorphous and ordered crystalline state with very fast crystallization kinetics. Due to this exceptional combination of properties phase-change materials find broad application in non-volatile optical memories such as CD, DVD or Bluray Disc. Furthermore, this class of materials demonstrates remarkable electrical transport phenomena in their disordered state, which have shown to be crucial for their application in electronic storage devices. The threshold switching phenomenon denotes the sudden decrease in resistivity beyond a critical electrical threshold field. The threshold switching phenomenon facilitates the phase transitions at practical small voltages. Below this threshold the amorphous state resistivity is thermally activated and is observed to increase with time. This effect known as resistance drift seriously hampers the development of multi-level storage devices. Hence, understanding the physical origins of threshold switching and resistance drift phenomena is crucial to improve non-volatile phase-change memories. Even though both phenomena are often attributed to localized defect states in the band gap, the defect state density in amorphous phase-change materials has remained poorly studied. Starting from a brief introduction of the physics of phase-change materials this thesis summarizes the most important models behind electrical switching and resistance drift with the aim to discuss the role of localized defect states. The centerpiece of this thesis is the investigation of defects state densities in different amorphous phase-change materials and electrical switching chalcogenides. On the basis of Modulated Photo Current (MPC) Experiments and Photothermal Deflection Spectroscopy, a sophisticated band model for the disordered phase of the binary phase-change alloy GeTe has been developed. By this direct experimental approach the band-model for a-Ge

  12. Electronic transport in amorphous phase-change materials

    Energy Technology Data Exchange (ETDEWEB)

    Luckas, Jennifer Maria

    2012-09-14

    Phase change materials combine a pronounced contrast in resistivity and reflectivity between their disordered amorphous and ordered crystalline state with very fast crystallization kinetics. Due to this exceptional combination of properties phase-change materials find broad application in non-volatile optical memories such as CD, DVD or Bluray Disc. Furthermore, this class of materials demonstrates remarkable electrical transport phenomena in their disordered state, which have shown to be crucial for their application in electronic storage devices. The threshold switching phenomenon denotes the sudden decrease in resistivity beyond a critical electrical threshold field. The threshold switching phenomenon facilitates the phase transitions at practical small voltages. Below this threshold the amorphous state resistivity is thermally activated and is observed to increase with time. This effect known as resistance drift seriously hampers the development of multi-level storage devices. Hence, understanding the physical origins of threshold switching and resistance drift phenomena is crucial to improve non-volatile phase-change memories. Even though both phenomena are often attributed to localized defect states in the band gap, the defect state density in amorphous phase-change materials has remained poorly studied. Starting from a brief introduction of the physics of phase-change materials this thesis summarizes the most important models behind electrical switching and resistance drift with the aim to discuss the role of localized defect states. The centerpiece of this thesis is the investigation of defects state densities in different amorphous phase-change materials and electrical switching chalcogenides. On the basis of Modulated Photo Current (MPC) Experiments and Photothermal Deflection Spectroscopy, a sophisticated band model for the disordered phase of the binary phase-change alloy GeTe has been developed. By this direct experimental approach the band-model for a-Ge

  13. Bipolar Disorder in Children

    Science.gov (United States)

    2014-01-01

    Although bipolar disorder historically was thought to only occur rarely in children and adolescents, there has been a significant increase in children and adolescents who are receiving this diagnosis more recently (Carlson, 2005). Nonetheless, the applicability of the current bipolar disorder diagnostic criteria for children, particularly preschool children, remains unclear, even though much work has been focused on this area. As a result, more work needs to be done to further the understanding of bipolar symptoms in children. It is hoped that this paper can assist psychologists and other health service providers in gleaning a snapshot of the literature in this area so that they can gain an understanding of the diagnostic criteria and other behaviors that may be relevant and be informed about potential approaches for assessment and treatment with children who meet bipolar disorder criteria. First, the history of bipolar symptoms and current diagnostic criteria will be discussed. Next, assessment strategies that may prove helpful for identifying bipolar disorder will be discussed. Then, treatments that may have relevance to children and their families will be discussed. Finally, conclusions regarding work with children who may have a bipolar disorder diagnosis will be offered. PMID:24800202

  14. Bipolar Disorder in Children

    Directory of Open Access Journals (Sweden)

    Kimberly Renk

    2014-01-01

    Full Text Available Although bipolar disorder historically was thought to only occur rarely in children and adolescents, there has been a significant increase in children and adolescents who are receiving this diagnosis more recently (Carlson, 2005. Nonetheless, the applicability of the current bipolar disorder diagnostic criteria for children, particularly preschool children, remains unclear, even though much work has been focused on this area. As a result, more work needs to be done to further the understanding of bipolar symptoms in children. It is hoped that this paper can assist psychologists and other health service providers in gleaning a snapshot of the literature in this area so that they can gain an understanding of the diagnostic criteria and other behaviors that may be relevant and be informed about potential approaches for assessment and treatment with children who meet bipolar disorder criteria. First, the history of bipolar symptoms and current diagnostic criteria will be discussed. Next, assessment strategies that may prove helpful for identifying bipolar disorder will be discussed. Then, treatments that may have relevance to children and their families will be discussed. Finally, conclusions regarding work with children who may have a bipolar disorder diagnosis will be offered.

  15. Genetics of bipolar disorder

    OpenAIRE

    Kerner, Berit

    2014-01-01

    Berit Kerner Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, Los Angeles, CA, USA Abstract: Bipolar disorder is a common, complex genetic disorder, but the mode of transmission remains to be discovered. Many researchers assume that common genomic variants carry some risk for manifesting the disease. The research community has celebrated the first genome-wide significant associations between common single nucleotide polymorphisms (SNPs) and bipolar ...

  16. [Antidepressants in bipolar disorder].

    Science.gov (United States)

    Courtet, P; Samalin, L; Olié, E

    2011-12-01

    Whereas mania defines the bipolar disorder, depression is the major challenge of treatment. In general, depressions are more frequent, longer, with a major prognostic impact in terms of disability and suicide. How should we treat a patient with bipolar depression? Antidepressants are the treatment of choice for depression, but not in the bipolar disorder. In this context, we have traditionally accepted that antidepressants are effective but they were inducing a significant risk of destabilization of the bipolar disorder, because of the transitions to mania and rapid cycling. Current data reconsider both the two aspects of this risk-benefit ratio. The effectiveness of antidepressants finally seems very limited, especially after the more recent studies with a robust methodology. Manic switches and rapid cycling may not be increased, particularly with new antidepressants and mood stabilizer combinations. The current literature reminds us that these course's modalities are inherent to the disease, with numerous risk factors, and among them, exposure to antidepressants. Who are the bipolar patients who only get the benefits of antidepressant treatment? Research will tell. They are in any case limited. How to navigate in our treatment strategies ? By choosing first drugs that demonstrated efficacy in bipolar depression. When the situation is more complex, "primum non nocere" should lead to support the prescription of the antidepressant in association with mood stabilizer. Copyright © 2011 L’Encéphale. Published by Elsevier Masson SAS.. All rights reserved.

  17. Anomalous activation of shallow B+ implants in Ge

    DEFF Research Database (Denmark)

    Yates, B.R.; Darby, B.L.; Rudawski, N.G.

    2011-01-01

    The electrical activation of B+ implantation at 2 keV to doses of 5.0×1013-5.0×1015 cm-2 in crystalline and pre-amorphized Ge following annealing at 400 °C for 1.0 h was studied using micro Hall effect measurements. Preamorphization improved activation for all samples with the samples implanted...

  18. Structural amorphous steels

    International Nuclear Information System (INIS)

    Lu, Z.P.; Liu, C.T.; Porter, W.D.; Thompson, J.R.

    2004-01-01

    Recent advancement in bulk metallic glasses, whose properties are usually superior to their crystalline counterparts, has stimulated great interest in fabricating bulk amorphous steels. While a great deal of effort has been devoted to this field, the fabrication of structural amorphous steels with large cross sections has remained an alchemist's dream because of the limited glass-forming ability (GFA) of these materials. Here we report the discovery of structural amorphous steels that can be cast into glasses with large cross-section sizes using conventional drop-casting methods. These new steels showed interesting physical, magnetic, and mechanical properties, along with high thermal stability. The underlying mechanisms for the superior GFA of these materials are discussed

  19. Growth Mechanism and Surface Structure of Ge Nanocrystals Prepared by Thermal Annealing of Cosputtered GeSiO Ternary Precursor

    Directory of Open Access Journals (Sweden)

    Bo Zhang

    2014-01-01

    Full Text Available Ge nanocrystals (Ge-ncs embedded in a SiO2 superlattice structure were prepared by magnetron cosputtering and postdeposition annealing. The formation of spherical nanocrystals was confirmed by transmission electron microscopy and their growth process was studied by a combination of spectroscopic techniques. The crystallinity volume fraction of Ge component was found to increase with crystallite size, but its overall low values indicated a coexistence of crystalline and noncrystalline phases. A reduction of Ge-O species was observed in the superlattice during thermal annealing, accompanied by a transition from oxygen-deficient silicon oxide to silicon dioxide. A growth mechanism involving phase separation of Ge suboxides (GeOx was then proposed to explain these findings and supplement the existing growth models for Ge-ncs in SiO2 films. Further analysis of the bonding structure of Ge atoms suggested that Ge-ncs are likely to have a core-shell structure with an amorphous-like surface layer, which is composed of GeSiO ternary complex. The surface layer thickness was extracted to be a few angstroms and equivalent to several atomic layer thicknesses.

  20. Depression and Bipolar Support Alliance

    Science.gov (United States)

    Depression and Bipolar Support Alliance Crisis Hotline Information Coping with a Crisis Suicide Prevention Information Psychiatric Hospitalization ... sign-up Education info, training, events Mood Disorders Depression Bipolar Disorder Anxiety Screening Center Co-occurring Illnesses/ ...

  1. Bipolar Affective Disorder and Migraine

    Directory of Open Access Journals (Sweden)

    Birk Engmann

    2012-01-01

    Full Text Available This paper consists of a case history and an overview of the relationship, aetiology, and treatment of comorbid bipolar disorder migraine patients. A MEDLINE literature search was used. Terms for the search were bipolar disorder bipolar depression, mania, migraine, mood stabilizer. Bipolar disorder and migraine cooccur at a relatively high rate. Bipolar II patients seem to have a higher risk of comorbid migraine than bipolar I patients have. The literature on the common roots of migraine and bipolar disorder, including both genetic and neuropathological approaches, is broadly discussed. Moreover, bipolar disorder and migraine are often combined with a variety of other affective disorders, and, furthermore, behavioural factors also play a role in the origin and course of the diseases. Approach to treatment options is also difficult. Several papers point out possible remedies, for example, valproate, topiramate, which acts on both diseases, but no first-choice treatments have been agreed upon yet.

  2. Impact of Ge profile on the performance of PNP SiGe HBT on thin film SOI

    Science.gov (United States)

    Misra, Prasanna K.; Qureshi, S.

    2012-10-01

    The pnp SiGe HBT on thin film SOI is investigated with different Ge profiles using 2D numerical simulations in MEDICI. The base current, collector current, DC current gain, AC voltage gain, unity current gain frequency and breakdown voltage is obtained for a 0.09 × 1.0 μm2 pnp SiGe HBT with triangular (0%-30%), trapezoidal (10%- 20%) and box (15%) Ge profiles in the base layer. The results obtained with the Ge profiles, has been analyzed and compared. The Ft BVCEO product for triangular, trapezoidal and box Ge profiles has been found as 190.8, 401, and 359.6 GHzV respectively. The tradeoff between voltage gain and unity current gain frequency for the Ge profiles has been analyzed. The simulation result suggests that the pnp SiGe HBT on thin film SOI with trapezoidal Ge profile is a potential candidate for the high speed complementary bipolar circuits that can be used in high performance mixed signal applications.

  3. Direct separation of short range order in intermixed nanocrystalline and amorphous phases

    International Nuclear Information System (INIS)

    Frenkel, Anatoly I.; Kolobov, Alexander V.; Robinson, Ian K.; Cross, Julie O.; Maeda, Yoshihito; Bouldin, Charles E.

    2002-01-01

    Diffraction anomalous fine-structure (DAFS) and extended x-ray absorption fine-structure (EXAFS) measurements were combined to determine short range order (SRO) about a single atomic type in a sample of mixed amorphous and nanocrystalline phases of germanium. EXAFS yields information about the SRO of all Ge atoms in the sample, while DAFS determines the SRO of only the ordered fraction. We determine that the first-shell distance distribution is bimodal; the nanocrystalline distance is the same as the bulk crystal, to within 0.01(2) A ring , but the mean amorphous Ge-Ge bond length is expanded by 0.076(19) Angstrom. This approach can be applied to many systems of mixed amorphous and nanocrystalline phases

  4. Ion beam induced epitaxy in Ge- and B- coimplanted silicon

    International Nuclear Information System (INIS)

    Hayashi, N.; Hasegawa, M.; Tanoue, H.; Takahashi, H.; Shimoyama, K.; Kuriyama, K.

    1992-01-01

    The epitaxial regrowth of amorphous surface layers in and Si substrate has been studied under irradiation with 400 keV Ar + ions at the temperature range from 300 to 435degC. The amorphous layers were obtained by Ge + implantation, followed by B + implantation. The ion beam assisted epitaxy was found to be sensitive to both the substrate orientation and the implanted Ge concentration, and the layer-by-layer epitaxial regrowth seemed to be precluded in Si layers with high doses of Ge implants, e.g., 2.5 x 10 15 ions/cm 2 . Electrical activation of implanted dopant B was also measured in the recrystallized Si layer. (author)

  5. Depressive and bipolar disorders

    DEFF Research Database (Denmark)

    Kessing, Lars Vedel; Hansen, Hanne Vibe; Demyttenaere, Koen

    2005-01-01

    BACKGROUND: There is increasing evidence that attitudes and beliefs are important in predicting adherence to treatment and medication in depressive and bipolar disorders. However, these attitudes have received little study in patients whose disorders were sufficiently severe to require...... hospitalization. METHOD: The Antidepressant Compliance Questionnaire (ADCQ) was mailed to a large population of patients with depressive or bipolar disorder, representative of patients treated in hospital settings in Denmark. RESULTS: Of the 1005 recipients, 49.9% responded to the letter. A large proportion....... Moreover, their partners agreed on these negative views. Women had a more negative view of the doctor-patient relationship than men, and patients with a depressive disorder had a more negative view of antidepressants than patients with bipolar disorder. The number of psychiatric hospitalizations...

  6. Leakage current in high-purity germanium detectors with amorphous semiconductor contacts

    Science.gov (United States)

    Looker, Q.; Amman, M.; Vetter, K.

    2015-03-01

    Amorphous semiconductor electrical contacts on high-purity Ge radiation detectors have become a valuable technology because they are simple to fabricate, result in thin dead layers, block both electron and hole injection, and can readily be finely segmented as needed for applications requiring imaging or particle tracking. Though significant numbers of detectors have been successfully produced for a variety of applications using the amorphous semiconductor contact technology, there remains a need to better understand the dependence of performance characteristics, particularly leakage current, on the fabrication process parameters so that the performance can be better optimized. To this end, we have performed a systematic study of leakage current on RF-sputter-deposited amorphous-Ge (a-Ge) and amorphous-Si (a-Si) contacts as a function of process and operational parameters including sputter gas pressure and composition, number of detector temperature cycles, and time spent at room temperature. The study focused primarily on the current resulting from electron injection at the contact. Significant findings from the study include that a-Si produces lower electron injection than a-Ge, the time the detector spends at room temperature rather than the number of temperature cycles experienced by the detector is the primary factor associated with leakage current change when the detector is warmed, and the time stability of the a-Ge contact depends on the sputter gas pressure with a higher pressure producing more stable characteristics.

  7. Novel multiple criteria decision making methods based on bipolar neu trosophic sets and bipolar neutrosophic graphs

    OpenAIRE

    Muhammad Akram; Musavarah Sarwar

    2017-01-01

    In this research article, we present certain notions of bipolar neutrosophic graphs. We study the dominating and independent sets of bipolar neutrosophic graphs. We describe novel multiple criteria decision making methods based on bipolar neutrosophic sets and bipolar neutrosophic graphs.

  8. Discrete bipolar universal integrals

    Czech Academy of Sciences Publication Activity Database

    Greco, S.; Mesiar, Radko; Rindone, F.

    2014-01-01

    Roč. 252, č. 1 (2014), s. 55-65 ISSN 0165-0114 R&D Projects: GA ČR GAP402/11/0378 Institutional support: RVO:67985556 Keywords : bipolar integral * universal integral * Choquet integral Subject RIV: BA - General Mathematics Impact factor: 1.986, year: 2014 http://library.utia.cas.cz/separaty/2014/E/mesiar-0432224.pdf

  9. [Spouses and bipolar disorder].

    Science.gov (United States)

    Ellouze, F; Ayedi, S; Cherif, W; Ben Abla, T; M'rad, M F

    2011-02-01

    To assess the quality of life of a population of spouses of bipolar patients compared with a control population. We conducted a cross-sectional study which included two groups: a group of 30 spouses of patients followed for bipolar I disorder according to DSM IV criteria and a second group of 30 subjects from the general population. Both groups were matched by age, sex, marital status and socioeconomic level. This device was designed to limit the differences between the two groups solely those of the bipolar illness. Evaluating the quality of life was achieved using the quality of life scale: SF-36. This is a scale that has already been translated and validated in dialect Arabic. Regarding sociodemographic variables, the two study groups differed only for: recreation, friendly relations and the couple relationship that included more and better skills among the control group. In the categorical approach, the quality of life was impaired in 60% of spouses and 40% of controls with a statistically significant difference. The following standardized dimensions: mental health (D4), limitation due to mental health (D5), life and relationship with others (D6) and perceived health (D8) and mental component (CM) were significantly altered in patients' spouses compared to controls. We found significant differences between the two groups for: overall average score (51.1 vs. 68.2), mental health (D4), limitation due to mental health (D5), life and relationship with others (D6), perceived health (D8) and perceived health (D8) standards. The impairment of quality of life of bipolar patients' spouses is related to the extra responsibility, stress, financial problems and health problems, stigma, and loss of security of the person loved. Considering the consequences that the appearance of bipolar disorder on the patient's spouse may have, certain measures must be proposed to improve their quality of life. Copyright © 2010 L'Encéphale, Paris. Published by Elsevier Masson SAS. All

  10. Crystallization behavior of Ge-doped eutectic Sb70Te30 films in optical disks

    Science.gov (United States)

    Khulbe, Pramod K.; Hurst, Terril; Horie, Michikazu; Mansuripur, Masud

    2002-10-01

    We report laser-induced crystallization behavior of binary Sb-Te and ternary Ge-doped eutectic Sb70Te30 thin film samples in a typical quadrilayer stack as used in phase-change optical disk data storage. Several experiments have been conducted on a two-laser static tester in which one laser operating in pulse mode writes crystalline marks on amorphous film or amorphous marks on crystalline film, while the second laser operating at low-power cw mode simultaneously monitors the progress of the crystalline or amorphous mark formation in real time in terms of the reflectivity variation. The results of this study show that the crystallization kinetics of this class of film is strongly growth dominant, which is significantly different from the crystallization kinetics of stochiometric Ge-Sb-Te compositions. In Sb-Te and Ge-doped eutectic Sb70Te30 thin-film samples, the crystallization behavior of the two forms of amorphous states, namely, as-deposited amorphous state and melt-quenched amorphous state, remains approximately same. We have also presented experiments showing the effect of the variation of the Sb/Te ratio and Ge doping on the crystallization behavior of these films.

  11. Ge nano-layer fabricated by high-fluence low-energy ion implantation

    International Nuclear Information System (INIS)

    Lu Tiecheng; Dun Shaobo; Hu Qiang; Zhang Songbao; An Zhu; Duan Yanmin; Zhu Sha; Wei Qiangmin; Wang Lumin

    2006-01-01

    A Ge nano-layer embedded in the surface layer of an amorphous SiO 2 film was fabricated by high-fluence low-energy ion implantation. The component, phase, nano-structure and luminescence properties of the nano-layer were studied by means of Rutherford backscattering, glancing incident X-ray diffraction, laser Raman scattering, transmission electron microscopy and photoluminescence. The relation between nano-particle characteristics and ion fluence was also studied. The results indicate that nano-crystalline Ge and nano-amorphous Ge particles coexist in the nano-layer and the ratio of nano-crystalline Ge to nano-particle Ge increases with increasing ion fluence. The intensity of photoluminescence from the nano-layer increases with increasing ion fluence also. Prepared with certain ion fluences, high-density nano-layers composed of uniform-sized nano-particles can be observed

  12. Amorphous Semiconductor Alloys

    Science.gov (United States)

    Madan, Arun

    1985-08-01

    Amorphous silicon (a-Si) based alloys have attracted a considerable amount of interest because of their applications in a wide variety of technologies. However, the major effort has concentrated on inexpensive photovoltaic device applications and has moved from a laboratory curiosity in the early 1970's to viable commercial applications in the 1980's. Impressive progress in this field has been made since the group at University of Dundee demonstrated that a low defect, device quality hydrogenated amorphous silicon (a-Si:H) 12 material could be produced using the radio frequency (r.f.) glow discharge in SiH4 gas ' and that the material could be doped n- and p-type.3 These results spurred a worldwide interest in a-Si based alloys, especially for photovoltaic devices which has resulted in a conversion efficiency approaching 12%. There is now a quest for even higher conversion efficiencies by using the multijunction cell approach. This necessitates the synthesis of new materials of differing bandgaps, which in principle amorphous semiconductors can achieve. In this article, we review some of this work and consider from a device and a materials point of view the hurdles which have to be overcome before this type of concept can be realized.

  13. ON BIPOLAR SINGLE VALUED NEUTROSOPHIC GRAPHS

    OpenAIRE

    Broumi, Said; Talea, Mohamed; Bakali, Assia; Smarandache, Florentin

    2016-01-01

    In this article, we combine the concept of bipolar neutrosophic set and graph theory. We introduce the notions of bipolar single valued neutrosophic graphs, strong bipolar single valued neutrosophic graphs, complete bipolar single valued neutrosophic graphs, regular bipolar single valued neutrosophic graphs and investigate some of their related properties.

  14. Comprehensive modeling of ion-implant amorphization in silicon

    International Nuclear Information System (INIS)

    Mok, K.R.C.; Jaraiz, M.; Martin-Bragado, I.; Rubio, J.E.; Castrillo, P.; Pinacho, R.; Srinivasan, M.P.; Benistant, F.

    2005-01-01

    A physically based model has been developed to simulate the ion-implant induced damage accumulation up to amorphization in silicon. Based on damage structures known as amorphous pockets (AP), which are three-dimensional, irregularly shaped agglomerates of interstitials (I) and vacancies (V) surrounded by crystalline silicon, the model is able to reproduce a wide range of experimental observations of damage accumulation and amorphization with interdependent implantation parameters. Instead of recrystallizing the I's and V's instantaneously, the recrystallization rate of an AP containing nI and mV is a function of its effective size, defined as min(n, m), irrespective of its internal spatial configuration. The parameters used in the model were calibrated using the experimental silicon amorphous-crystalline transition temperature as a function of dose rate for C, Si, and Ge. The model is able to show the superlinear damage build-up with dose, the extent of amorphous layer and the superadditivity effect of polyatomic ions

  15. Early Intervention in Bipolar Disorder.

    Science.gov (United States)

    Vieta, Eduard; Salagre, Estela; Grande, Iria; Carvalho, André F; Fernandes, Brisa S; Berk, Michael; Birmaher, Boris; Tohen, Mauricio; Suppes, Trisha

    2018-01-24

    Bipolar disorder is a recurrent disorder that affects more than 1% of the world population and usually has its onset during youth. Its chronic course is associated with high rates of morbidity and mortality, making bipolar disorder one of the main causes of disability among young and working-age people. The implementation of early intervention strategies may help to change the outcome of the illness and avert potentially irreversible harm to patients with bipolar disorder, as early phases may be more responsive to treatment and may need less aggressive therapies. Early intervention in bipolar disorder is gaining momentum. Current evidence emerging from longitudinal studies indicates that parental early-onset bipolar disorder is the most consistent risk factor for bipolar disorder. Longitudinal studies also indicate that a full-blown manic episode is often preceded by a variety of prodromal symptoms, particularly subsyndromal manic symptoms, therefore supporting the existence of an at-risk state in bipolar disorder that could be targeted through early intervention. There are also identifiable risk factors that influence the course of bipolar disorder, some of them potentially modifiable. Valid biomarkers or diagnosis tools to help clinicians identify individuals at high risk of conversion to bipolar disorder are still lacking, although there are some promising early results. Pending more solid evidence on the best treatment strategy in early phases of bipolar disorder, physicians should carefully weigh the risks and benefits of each intervention. Further studies will provide the evidence needed to finish shaping the concept of early intervention.

  16. The Stabilization of Amorphous Zopiclone in an Amorphous Solid Dispersion.

    Science.gov (United States)

    Milne, Marnus; Liebenberg, Wilna; Aucamp, Marique

    2015-10-01

    Zopiclone is a poorly soluble psychotherapeutic agent. The aim of this study was to prepare and characterize an amorphous form of zopiclone as well as the characterization and performance of a stable amorphous solid dispersion. The amorphous form was prepared by the well-known method of quench-cooling of the melt. The solid dispersion was prepared by a solvent evaporation method of zopiclone, polyvinylpyrrolidone-25 (PVP-25), and methanol, followed by freeze-drying. The physico-chemical properties and stability of amorphous zopiclone and the solid dispersion was studied using differential scanning calorimetry (DSC), infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), hot-stage microscopy (HSM), X-ray diffractometry (XRD), solubility, and dissolution studies. The zopiclone amorphous solid-state form was determined to be a fragile glass; it was concluded that the stability of the amorphous form is influenced by both temperature and water. Exposure of amorphous zopiclone to moisture results in rapid transformation of the amorphous form to the crystalline dihydrated form. In comparison, the amorphous solid dispersion proved to be more stable with increased aqueous solubility.

  17. Unidirectional threshold switching in Ag/Si-based electrochemical metallization cells for high-density bipolar RRAM applications

    Science.gov (United States)

    Wang, Chao; Song, Bing; Li, Qingjiang; Zeng, Zhongming

    2018-03-01

    We herein present a novel unidirectional threshold selector for cross-point bipolar RRAM array. The proposed Ag/amorphous Si based threshold selector showed excellent threshold characteristics in positive field, such as high selectivity ( 105), steep slope (experiments showed that the undesired sneak was significantly suppressed, indicating its potentiality for high-density integrated nonvolatile memory applications.

  18. Life expectancy in bipolar disorder

    DEFF Research Database (Denmark)

    Kessing, Lars Vedel; Vradi, Eleni; Andersen, Per Kragh

    2015-01-01

    OBJECTIVE: Life expectancy in patients with bipolar disorder has been reported to be decreased by 11 to 20 years. These calculations are based on data for individuals at the age of 15 years. However, this may be misleading for patients with bipolar disorder in general as most patients have a later...... onset of illness. The aim of the present study was to calculate the remaining life expectancy for patients of different ages with a diagnosis of bipolar disorder. METHODS: Using nationwide registers of all inpatient and outpatient contacts to all psychiatric hospitals in Denmark from 1970 to 2012 we...... remaining life expectancy in bipolar disorder and that of the general population decreased with age, indicating that patients with bipolar disorder start losing life-years during early and mid-adulthood. CONCLUSIONS: Life expectancy in bipolar disorder is decreased substantially, but less so than previously...

  19. Bipolar Disorder and Alcoholism: Are They Related?

    Science.gov (United States)

    ... Is there a connection between bipolar disorder and alcoholism? Answers from Daniel K. Hall-Flavin, M.D. Bipolar disorder and alcoholism often occur together. Although the association between bipolar ...

  20. [Creativity and bipolar disorder].

    Science.gov (United States)

    Maçkalı, Zeynep; Gülöksüz, Sinan; Oral, Timuçin

    2014-01-01

    The relationship between creativity and bipolar disorder has been an intriguing topic since ancient times. Early studies focused on describing characteristics of creative people. From the last quarter of the twentieth century, researchers began to focus on the relationship between mood disorders and creativity. Initially, the studies were based on biographical texts and the obtained results indicated a relationship between these two concepts. The limitations of the retrospective studies led the researchers to develop systematic investigations into this area. The systematic studies that have focused on artistic creativity have examined both the prevalence of mood disorders and the creative process. In addition, a group of researchers addressed the relationship in terms of affective temperaments. Through the end of the 90's, the scope of creativity was widened and the notion of everyday creativity was proposed. The emergence of this notion led researchers to investigate the associations of the creative process in ordinary (non-artist) individuals. In this review, the descriptions of creativity and creative process are mentioned. Also, the creative process is addressed with regards to bipolar disorder. Then, the relationship between creativity and bipolar disorder are evaluated in terms of aforementioned studies (biographical, systematic, psychobiographical, affective temperaments). In addition, a new model, the "Shared Vulnerability Model" which was developed to explain the relationship between creativity and psychopathology is introduced. Finally, the methodological limitations and the suggestions for resolving these limitations are included.

  1. Bipolar Disorder and Diabetes Mellitus

    Directory of Open Access Journals (Sweden)

    Sermin Kesebir

    2010-04-01

    Full Text Available Comorbid endocrine and cardiovascular situations with bipolar disorder usually result from the bipolar disorder itself or as a consequence of its treatment. With habits and lifestyle, genetic tendency and side effects, this situation is becoming more striking. Subpopulations of bipolar disorders patients should be considered at high risk for diabetes mellitus. The prevalence of diabetes mellitus in bipolar disorder may be three times greater than in the general population. Comorbidity of diabetes causes a pathophysiological overlapping in the neurobiological webs of bipolar cases. Signal mechanisms of glycocorticoid/insulin and immunoinflammatory effector systems are junction points that point out the pathophysiology between bipolar disorder and general medical cases susceptible to stress. Glycogen synthetase kinase (GSK-3 is a serine/treonine kinase and inhibits the transport of glucose stimulated by insulin. It is affected in diabetes, cancer, inflammation, Alzheimer disease and bipolar disorder. Hypoglycemic effect of lithium occurs via inhibiting glycogen synthetase kinase. When comorbid with diabetes, the other disease -for example bipolar disorder, especially during its acute manic episodes-, causes a serious situation that presents its influences for a lifetime. Choosing pharmacological treatment and treatment adherence are another important interrelated areas. The aim of this article is to discuss and review the etiological, clinical and therapeutic properties of diabetes mellitus and bipolar disorder comorbidity.

  2. Linear and non-linear optical properties of amorphous Se and ...

    Indian Academy of Sciences (India)

    has been reported to be used in optical memory applica- tions, but in crystalline state it can be used in IR detector, solar cells, a compound semiconductor heterostructure [6–. 8]. ..... A clear red shift of the absorption edge was observed with the addition of Ge, Ga and Zn with 5 at.% to the amorphous Se. The inset of figure 3.

  3. Charge trapping of Ge-nanocrystals embedded in TaZrO{sub x} dielectric films

    Energy Technology Data Exchange (ETDEWEB)

    Lehninger, D., E-mail: David.Lehninger@physik.tu-freiberg.de; Seidel, P.; Geyer, M.; Schneider, F.; Heitmann, J. [Institute of Applied Physics, TU Bergakademie Freiberg, D-09596 Freiberg (Germany); Klemm, V.; Rafaja, D. [Institute of Materials Science, TU Bergakademie Freiberg, D-09596 Freiberg (Germany); Borany, J. von [Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, D-01314 Dresden (Germany)

    2015-01-12

    Ge-nanocrystals (NCs) were synthesized in amorphous TaZrO{sub x} by thermal annealing of co-sputtered Ge-TaZrO{sub x} layers. Formation of spherical shaped Ge-NCs with small variation of size, areal density, and depth distribution was confirmed by high-resolution transmission electron microscopy. The charge storage characteristics of the Ge-NCs were investigated by capacitance-voltage and constant-capacity measurements using metal-insulator-semiconductor structures. Samples with Ge-NCs exhibit a maximum memory window of 5 V by sweeping the bias voltage from −7 V to 7 V and back. Below this maximum, the width of the memory window can be controlled by the bias voltage. The fitted slope of the memory window versus bias voltage characteristics is very close to 1 for samples with one layer Ge-NCs. A second layer Ge-NCs does not result in a second flat stair in the memory window characteristics. Constant-capacity measurements indicate charge storage in trapping centers at the interfaces between the Ge-NCs and the surrounding materials (amorphous matrix/tunneling oxide). Charge loss occurs by thermal detrapping and subsequent band-to-band tunneling. Reference samples without Ge-NCs do not show any memory window.

  4. Charge trapping of Ge-nanocrystals embedded in TaZrOx dielectric films

    International Nuclear Information System (INIS)

    Lehninger, D.; Seidel, P.; Geyer, M.; Schneider, F.; Heitmann, J.; Klemm, V.; Rafaja, D.; Borany, J. von

    2015-01-01

    Ge-nanocrystals (NCs) were synthesized in amorphous TaZrO x by thermal annealing of co-sputtered Ge-TaZrO x layers. Formation of spherical shaped Ge-NCs with small variation of size, areal density, and depth distribution was confirmed by high-resolution transmission electron microscopy. The charge storage characteristics of the Ge-NCs were investigated by capacitance-voltage and constant-capacity measurements using metal-insulator-semiconductor structures. Samples with Ge-NCs exhibit a maximum memory window of 5 V by sweeping the bias voltage from −7 V to 7 V and back. Below this maximum, the width of the memory window can be controlled by the bias voltage. The fitted slope of the memory window versus bias voltage characteristics is very close to 1 for samples with one layer Ge-NCs. A second layer Ge-NCs does not result in a second flat stair in the memory window characteristics. Constant-capacity measurements indicate charge storage in trapping centers at the interfaces between the Ge-NCs and the surrounding materials (amorphous matrix/tunneling oxide). Charge loss occurs by thermal detrapping and subsequent band-to-band tunneling. Reference samples without Ge-NCs do not show any memory window

  5. De-embedding and Modelling of pnp SiGe HBTs

    DEFF Research Database (Denmark)

    Hadziabdic, Dzenan; Jiang, Chenhui; Johansen, Tom Keinicke

    2007-01-01

    In this work we present a direct parameter extraction procedure for SiGe pnp heterojunction bipolar transistor (HBT) large-signal and small-signal models. Test structure parasitics are removed from the measured small-signal parameters using an open-short de-embedding technique, improved to account...

  6. SiGe/Si electronics and optoelectronics

    Energy Technology Data Exchange (ETDEWEB)

    Wang, K.L.; Karunasiri, R.P.G. [Univ. of California, Los Angeles, CA (United States)

    1993-05-01

    Recently, there is an increased interest in the use of SiGe layered material for integration with Si technology. SiGe offers the opportunity for the first time to realize the advantages of heterojunctions in Si-based technology. In this article, the present status of the SiGe epitaxial growth techniques will be discussed from the point of view of device application. New directions will be presented. Next, electronic devices to be reviewed include bipolars and field effect transistors. The progress of tunneling devices will also be discussed. Then, the realization of quantum wells and superlattices for optoelectronics will be discussed. Then, the realization of quantum wells and superlattices for optoelectronics will be discussed. These will include Si-based detectors and modulators based on interband and intersubband transitions. One of the focuses will be the normal incidence operation for intersubband devices. Finally, the current status in the quest of light emitters will be briefly addressed. 44 refs., 15 figs.

  7. High (1 1 1) orientation poly-Ge film fabricated by Al induced crystallization without the introduction of AlO{sub x} interlayer

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Peng; Li, Xin; Liu, Hanhui; Lai, Shumei; Chen, Yuye; Xu, Yihong; Chen, Songyan, E-mail: sychen@xmu.edu.cn; Li, Cheng; Huang, Wei; Tang, Dingliang

    2015-12-15

    High (1 1 1) orientation poly-Ge film was fabricated by Al induced crystallization (AIC), where Al and amorphous Ge (a-Ge) layers were continuously deposited by magnetron sputtering, avoiding the deliberate introduction of an AlO{sub x} interlayer. To improve the quality of poly-Ge film, the ratio of thicknesses of Al and a-Ge was adjusted. Electron backscattered diffraction (EBSD) results revealed that the (1 1 1) fraction of poly-Ge film reached 97% and the average crystal grain size surpassed 100 μm.

  8. The impact of bipolar depression.

    Science.gov (United States)

    Post, Robert M

    2005-01-01

    Bipolar disorder is a chronic, intermittent illness that is associated with high morbidity and mortality. In addition, patients with bipolar disorder often have comorbid psychiatric conditions (such as anxiety disorders, alcohol or substance abuse, and eating disorders) or medical disorders (such as obesity), which result in increased burden of illness for the patients, family members, and treating clinicians. Although bipolar disorder consists of recurring episodes of mania and depression, patients spend more time depressed than manic. Bipolar depression is associated with a greater risk of suicide and of impairment in work, social, or family life than mania. This health burden also results in direct and indirect economic costs to the individual and society at large. Bipolar depression is often undiagnosed or misdiagnosed as unipolar depression, resulting in incorrect or inadequate treatment. Available treatments for bipolar depression include medications such as lithium, selected anticonvulsants, and the atypical antipsychotics. Traditional antidepressants are not recommended as monotherapy for bipolar depression as they can induce switching to mania. Early and accurate diagnosis, aggressive management, and earlier prophylactic treatment regimens are needed to overcome the impact of depressive episodes in patients with bipolar disorder.

  9. Collective-pinning properties of superconducting a-NbxGe and a-MoxSi films

    International Nuclear Information System (INIS)

    Woerdenweber, R.

    1987-01-01

    This thesis describes a study of superconducting flux pinning in amorphous NbGe and MoSi films of various compositions and thickness. Amorphous NbGe and MoSi alloys belong to the weak-coupling type-II superconductors in the extreme dirty limit. This feature enables to determine several important superconducting parameters from well-known theoretical expressions. It is also responsible for the weak pinning, which is necessary to observe the two-dimensional collective pinning properties according to the Larkin-Ovchinnikov theory. (Auth.)

  10. Electronic and atomic structure of Ge2Sb2Te5 phase change memory material

    International Nuclear Information System (INIS)

    Robertson, J.; Xiong, K.; Peacock, P.W.

    2007-01-01

    Electronic structure calculations are presented for various model structures of the crystalline and amorphous phases of Ge 2 Sb 2 Te 5 . The structures are all found to possess a band gap of order 0.5 eV, indicating closed shell behaviour. It is pointed out that structural vacancies in A7-like Ge 2 Sb 2 Te 5 are not electronically active. In addition, A7-like structures do not support valence alternation pair defects, which are one model of the conduction processes in the amorphous phase in non-volatile memories

  11. Scientific attitudes towards bipolar disorders

    Directory of Open Access Journals (Sweden)

    Mohammad-Hossein Biglu

    2014-02-01

    Full Text Available Introduction: Bipolar disorder is a psychiatric condition that is also called manic-depressive disease. It causes unusual changes in mood, energy, activity levels, and the ability to carry out day-to-day tasks. In the present study, 3 sets of data were considered and analyzed: first, all papers categorized under Bipolar Disorders in Science Citation Index Expanded (SCI-E database through 2001-2011; second, papers published by the international journal of Bipolar Disorders indexed in SCI-E during a period of 11 years; and third, all papers distributed by the international journal of Bipolar Disorders indexed in MEDLINE during the period of study. Methods: The SCI-E database was used to extract all papers indexed with the topic of Bipolar Disorders as well as all papers published by The International Journal of Bipolar Disorders. Extraction of data from MEDLINE was restricted to the journals name from setting menu. The Science of Science Tool was used to map the co-authorship network of papers published by The International Journal of Bipolar Disorders through 2009-2011. Results: Analysis of data showed that the majority of publications in the subject area of bipolar disorders indexed in SCI-E were published by The International Journal of Bipolar Disorders. Although journal articles consisted of 59% of the total publication type in SCI-E, 65% of publications distributed by The Journal of Bipolar Disorders were in the form of meetingabstracts. Journal articles consisted of only 23% of the total publications. USA was the leading country regarding sharing data in the field of bipolar disorders followed by England, Canada, and Germany. Conclusion: The editorial policy of The International Journal of Bipolar Disorders has been focused on new themes and new ways of researching in the subject area of bipolar disorder. Regarding the selection of papers for indexing, the SCI-E database selects data more comprehensively than MEDLINE. The number of papers

  12. Genetics of bipolar disorder

    Directory of Open Access Journals (Sweden)

    Kerner B

    2014-02-01

    Full Text Available Berit Kerner Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, Los Angeles, CA, USA Abstract: Bipolar disorder is a common, complex genetic disorder, but the mode of transmission remains to be discovered. Many researchers assume that common genomic variants carry some risk for manifesting the disease. The research community has celebrated the first genome-wide significant associations between common single nucleotide polymorphisms (SNPs and bipolar disorder. Currently, attempts are under way to translate these findings into clinical practice, genetic counseling, and predictive testing. However, some experts remain cautious. After all, common variants explain only a very small percentage of the genetic risk, and functional consequences of the discovered SNPs are inconclusive. Furthermore, the associated SNPs are not disease specific, and the majority of individuals with a “risk” allele are healthy. On the other hand, population-based genome-wide studies in psychiatric disorders have rediscovered rare structural variants and mutations in genes, which were previously known to cause genetic syndromes and monogenic Mendelian disorders. In many Mendelian syndromes, psychiatric symptoms are prevalent. Although these conditions do not fit the classic description of any specific psychiatric disorder, they often show nonspecific psychiatric symptoms that cross diagnostic boundaries, including intellectual disability, behavioral abnormalities, mood disorders, anxiety disorders, attention deficit, impulse control deficit, and psychosis. Although testing for chromosomal disorders and monogenic Mendelian disorders is well established, testing for common variants is still controversial. The standard concept of genetic testing includes at least three broad criteria that need to be fulfilled before new genetic tests should be introduced: analytical validity, clinical validity, and clinical utility. These criteria are

  13. Amorphous Gyroscopic Topological Metamaterials

    Science.gov (United States)

    Mitchell, Noah P.; Nash, Lisa M.; Hexner, Daniel; Turner, Ari M.; Irvine, William T. M.

    Mechanical topological metamaterials display striking mechanical responses, such as unidirectional surface modes that are impervious to disorder. This behavior arises from the topology of their vibrational spectra. All examples of topological metamaterials to date are finely-tuned structures such as crystalline lattices or jammed packings. Here, we present robust recipes for building amorphous topological metamaterials with arbitrary underlying structure and no long-range order. Using interacting gyroscopes as a model system, we demonstrate through experiment, simulation, and theoretical methods that the local geometry and interactions are sufficient to generate topological mobility gaps, allowing for spatially-resolved, real-space calculations of the Chern number. The robustness of our approach enables the design and self-assembly of non-crystalline materials with protected, unidirectional waveguides on the micro and macro scale.

  14. Gold fillings unravel the vacancy role in the phase transition of GeTe

    Science.gov (United States)

    Feng, Jinlong; Xu, Meng; Wang, Xiaojie; Lin, Qi; Cheng, Xiaomin; Xu, Ming; Tong, Hao; Miao, Xiangshui

    2018-02-01

    Phase change memory (PCM) is an important candidate for future memory devices. The crystalline phase of PCM materials contains abundant intrinsic vacancies, which plays an important role in the rapid phase transition upon memory switching. However, few experimental efforts have been invested to study these invisible entities. In this work, Au dopants are alloyed into the crystalline GeTe to fill the intrinsic Ge vacancies so that the role of these vacancies in the amorphization of GeTe can be indirectly studied. As a result, the reduction of Ge vacancies induced by Au dopants hampers the amorphization of GeTe as the activation energy of this process becomes higher. This is because the vacancy-interrupted lattice can be "repaired" by Au dopants with the recovery of bond connectivity. Our results demonstrate the importance of vacancies in the phase transition of chalcogenides, and we employ the percolation theory to explain the impact of these intrinsic defects on this vacancy-ridden crystal quantitatively. Specifically, the threshold of amorphization increases with the decrease in vacancies. The understanding of the vacancy effect sheds light on the long-standing puzzle of the mechanism of ultra-fast phase transition in PCMs. It also paves the way for designing low-power-consumption electronic devices by reducing the threshold of amorphization in chalcogenides.

  15. Fabrication of SiGe/Ge core-shell nanowires by oxidation of SiGe

    OpenAIRE

    Kløw, Frode

    2011-01-01

    As Si technology is reaching its limits in solar cell and transistor applications, ways to improve these devices are being investigated. This study looks at the fabrication process of SiGe/Ge core-shell nanowires (NWs). Larger SiGe column structures can be oxidized to reduce their size and create a SiGe/Ge core-shell structure with a layer of SiO2 on the outside. Initially, SiGe dry oxidation was investigated in epitaxially grown SiGe films with 15% and 20% Ge, focusing on the Ge pileup r...

  16. [Ge=Ge](4-) Dumbbells in the Zintl Phase Li3NaGe2.

    Science.gov (United States)

    Ruschewitz, Uwe

    2016-03-01

    Ge-Ge double bonds: The reaction of elemental lithium, sodium, and germanium at 750 °C results in the Zintl phase Li3NaGe2 , which, according to the Zintl-Klemm concept, contains [Ge=Ge](4-) dumbbells with unprecedented short Ge-Ge distances. Based on structural, spectroscopic, and theoretical considerations, convincing evidence is given that Ge-Ge double bonds are in fact present. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Novel multiple criteria decision making methods based on bipolar neutrosophic sets and bipolar neutrosophic graphs

    OpenAIRE

    Muhammad, Akram; Musavarah, Sarwar

    2016-01-01

    In this research study, we introduce the concept of bipolar neutrosophic graphs. We present the dominating and independent sets of bipolar neutrosophic graphs. We describe novel multiple criteria decision making methods based on bipolar neutrosophic sets and bipolar neutrosophic graphs. We also develop an algorithm for computing domination in bipolar neutrosophic graphs.

  18. Study of Ge loss during Ge condensation process

    International Nuclear Information System (INIS)

    Xue, Z.Y.; Di, Z.F.; Ye, L.; Mu, Z.Q.; Chen, D.; Wei, X.; Zhang, M.; Wang, X.

    2014-01-01

    Ge loss during Ge condensation process was investigated by transmission electron microscopy, Raman spectroscopy, secondary ion mass spectrometry and Rutherford backscattering spectrometry. This work reveals that Ge loss can be attributed to the Ge oxidation at SiO 2 /SiGe interface, Ge diffusion in SiO 2 layers and Ge trapped at buried SiO 2 /Si interface. During Ge condensation process, with the increase of the Ge content, the Si atoms become insufficient for selective oxidation at the oxide/SiGe interface. Consequently, the Si and Ge are oxidized simultaneously. When the Ge composition in SiGe layer increases further and approaches 100%, the Ge atoms begin to diffuse into the top SiO 2 layer and buried SiO 2 layer. However, the X-ray photoelectron spectrometry analysis manifests that the chemical states of the Ge in top SiO 2 layer are different from those in buried SiO 2 layer, as the Ge atoms diffused into top SiO 2 layer are oxidized to form GeO 2 in the subsequent oxidation step. With the increase of the diffusion time, a quantity of Ge atoms diffuse through buried SiO 2 layer and pile up at buried SiO 2 /Si interface due to the interfacial trapping. The SiO 2 /Si interface acts like a pump, absorbing Ge from a Ge layer continuously through a pipe-buried SiO 2 layer. With the progress of Ge condensation process, the quantity of Ge accumulated at SiO 2 /Si interface increases remarkably. - Highlights: • Ge loss during Ge condensation process is attributed to the Ge oxidation at SiO 2 /SiGe interface. • Ge diffusion in SiO 2 layers and Ge trapped at buried SiO 2 /Si interface • When Ge content in SiGe layer approaches 100%, Ge diffusion into the SiO 2 layer is observed. • Ge then gradually diffuses through buried SiO 2 layer and pile up at SiO 2 /Si interface

  19. Aging mechanisms in amorphous phase-change materials.

    Science.gov (United States)

    Raty, Jean Yves; Zhang, Wei; Luckas, Jennifer; Chen, Chao; Mazzarello, Riccardo; Bichara, Christophe; Wuttig, Matthias

    2015-06-24

    Aging is a ubiquitous phenomenon in glasses. In the case of phase-change materials, it leads to a drift in the electrical resistance, which hinders the development of ultrahigh density storage devices. Here we elucidate the aging process in amorphous GeTe, a prototypical phase-change material, by advanced numerical simulations, photothermal deflection spectroscopy and impedance spectroscopy experiments. We show that aging is accompanied by a progressive change of the local chemical order towards the crystalline one. Yet, the glass evolves towards a covalent amorphous network with increasing Peierls distortion, whose structural and electronic properties drift away from those of the resonantly bonded crystal. This behaviour sets phase-change materials apart from conventional glass-forming systems, which display the same local structure and bonding in both phases.

  20. Bipolar pulse forming line

    Science.gov (United States)

    Rhodes, Mark A.

    2008-10-21

    A bipolar pulse forming transmission line module for linear induction accelerators having first, second, third, fourth, and fifth planar conductors which form an interleaved stack with dielectric layers between the conductors. Each conductor has a first end, and a second end adjacent an acceleration axis. The first and second planar conductors are connected to each other at the second ends, the fourth and fifth planar conductors are connected to each other at the second ends, and the first and fifth planar conductors are connected to each other at the first ends via a shorting plate adjacent the first ends. The third planar conductor is electrically connectable to a high voltage source, and an internal switch functions to short a high voltage from the first end of the third planar conductor to the first end of the fourth planar conductor to produce a bipolar pulse at the acceleration axis with a zero net time integral. Improved access to the switch is enabled by an aperture through the shorting plate and the proximity of the aperture to the switch.

  1. Atomic force microscopy measurements of crystal nucleation and growth rates in thin films of amorphous Te alloys

    Science.gov (United States)

    Kalb, J.; Spaepen, F.; Wuttig, M.

    2004-06-01

    Ex situ atomic force microscopy in combination with a high-precision furnace has been employed for a systematic study of crystallization kinetics of sputtered amorphous Ag0.055In0.065Sb0.59Te0.29, Ge4Sb1Te5, and Ge2Sb2Te5 thin films used for optical data storage. Direct observation of crystals enabled us to establish the temperature dependence of the crystal nucleation rate and crystal growth velocity around 150°C. While these alloys exhibited similar crystal growth characteristics, the crystal nucleation behavior of Ag0.055In0.065Sb0.59Te0.29 differed significantly from that of Ge4Sb1Te5 and Ge2Sb2Te5. These observations provide an explanation for the different recrystallization mechanisms observed upon laser heating of amorphous marks.

  2. Kinetically Controlled Two-Step Amorphization and Amorphous-Amorphous Transition in Ice

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Chuanlong; Yong, Xue; Tse, John S.; Smith, Jesse S.; Sinogeikin, Stanislav V.; Kenney-Benson, Curtis; Shen, Guoyin

    2017-09-01

    We report the results of in situ structural characterization of the amorphization of crystalline ice Ih under compression and the relaxation of high-density amorphous (HDA) ice under decompression at temperatures between 96 and 160 K by synchrotron x-ray diffraction. The results show that ice Ih transforms to an intermediate crystalline phase at 100 K prior to complete amorphization, which is supported by molecular dynamics calculations. The phase transition pathways show clear temperature dependence: direct amorphization without an intermediate phase is observed at 133 K, while at 145 K a direct Ih-to-IX transformation is observed; decompression of HDA shows a transition to low-density amorphous ice at 96 K and ~ 1 Pa , to ice Ic at 135 K and to ice IX at 145 K. These observations show that the amorphization of compressed ice Ih and the recrystallization of decompressed HDA are strongly dependent on temperature and controlled by kinetic barriers. Pressure-induced amorphous ice is an intermediate state in the phase transition from the connected H-bond water network in low pressure ices to the independent and interpenetrating H-bond network of high-pressure ices.

  3. The reliability studies of nano-engineered SiGe HBTs using Pelletron accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Prakash, A. P. Gnana, E-mail: gnanaprakash@physics.uni-mysore.ac.in; Praveen, K. C. [Department of Studies in Physics, University of Mysore, Manasagangotri, Mysore, Karnataka-570006 (India); Pushpa, N. [Department of PG Studies in Physics, JSS College, Ooty Road, Mysore-570025 (India); Cressler, John D. [School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA, 30332 (United States)

    2015-05-15

    The effects of high energy ions on the electrical characteristics of silicon-germanium heterojunction bipolar transistors (SiGe HBTs) were studied in the total dose of ranging from 600 krad to 100 Mrad (Si). The two generations (50 GHz and 200 GHz) of SiGe HBTs were exposed to 50 MeV lithium, 75 MeV boron and 100 MeV oxygen ions. The electrical characteristics of SiGe HBTs were studied before and after irradiation. The SiGe HBTs were exposed to {sup 60}Co gamma radiation in the same total dose. The results are systematically compared in order to understand the interaction of ions and ionizing radiation with SiGe HBTs.

  4. The reliability studies of nano-engineered SiGe HBTs using Pelletron accelerator

    Science.gov (United States)

    Prakash, A. P. Gnana; Praveen, K. C.; Pushpa, N.; Cressler, John D.

    2015-05-01

    The effects of high energy ions on the electrical characteristics of silicon-germanium heterojunction bipolar transistors (SiGe HBTs) were studied in the total dose of ranging from 600 krad to 100 Mrad (Si). The two generations (50 GHz and 200 GHz) of SiGe HBTs were exposed to 50 MeV lithium, 75 MeV boron and 100 MeV oxygen ions. The electrical characteristics of SiGe HBTs were studied before and after irradiation. The SiGe HBTs were exposed to 60Co gamma radiation in the same total dose. The results are systematically compared in order to understand the interaction of ions and ionizing radiation with SiGe HBTs.

  5. Asenapine for bipolar disorder

    Directory of Open Access Journals (Sweden)

    Scheidemantel T

    2015-12-01

    Full Text Available Thomas Scheidemantel,1 Irina Korobkova,2 Soham Rej,3,4 Martha Sajatovic1,2 1University Hospitals Case Medical Center, 2Case Western Reserve University School of Medicine, Cleveland, OH, USA; 3Department of Psychiatry, University of Toronto, Toronto, ON, 4Geri PARTy Research Group, Jewish General Hospital, Montreal, QC, Canada Abstract: Asenapine (Saphris® is an atypical antipsychotic drug which has been approved by the US Food and Drug Administration for the treatment of schizophrenia in adults, as well as the treatment of acute manic or mixed episodes of bipolar I in both adult and pediatric populations. Asenapine is a tetracyclic drug with antidopaminergic and antiserotonergic activity with a unique sublingual route of administration. In this review, we examine and summarize the available literature on the safety, efficacy, and tolerability of asenapine in the treatment of bipolar disorder (BD. Data from randomized, double-blind trials comparing asenapine to placebo or olanzapine in the treatment of acute manic or mixed episodes showed asenapine to be an effective monotherapy treatment in clinical settings; asenapine outperformed placebo and showed noninferior performance to olanzapine based on improvement in the Young Mania Rating Scale scores. There are limited data available on the use of asenapine in the treatment of depressive symptoms of BD, or in the maintenance phase of BD. The available data are inconclusive, suggesting the need for more robust data from prospective trials in these clinical domains. The most commonly reported adverse effect associated with use of asenapine is somnolence. However, the somnolence associated with asenapine use did not cause significant rates of discontinuation. While asenapine was associated with weight gain when compared to placebo, it appeared to be modest when compared to other atypical antipsychotics, and its propensity to cause increases in hemoglobin A1c or serum lipid levels appeared to be

  6. Three-dimensional nanomechanical mapping of amorphous and crystalline phase transitions in phase-change materials.

    Science.gov (United States)

    Grishin, Ilja; Huey, Bryan D; Kolosov, Oleg V

    2013-11-13

    The nanostructure of micrometer-sized domains (bits) in phase-change materials (PCM) that undergo switching between amorphous and crystalline phases plays a key role in the performance of optical PCM-based memories. Here, we explore the dynamics of such phase transitions by mapping PCM nanostructures in three dimensions with nanoscale resolution by combining precision Ar ion beam cross-sectional polishing and nanomechanical ultrasonic force microscopy (UFM) mapping. Surface and bulk phase changes of laser written submicrometer to micrometer sized amorphous-to-crystalline (SET) and crystalline-to-amorphous (RESET) bits in chalcogenide Ge2Sb2Te5 PCM are observed with 10-20 nm lateral and 4 nm depth resolution. UFM mapping shows that the Young's moduli of crystalline SET bits exceed the moduli of amorphous areas by 11 ± 2%, with crystalline content extending from a few nanometers to 50 nm in depth depending on the energy of the switching pulses. The RESET bits written with 50 ps pulses reveal shallower depth penetration and show 30-50 nm lateral and few nanometer vertical wavelike topography that is anticorrelated with the elastic modulus distribution. Reverse switching of amorphous RESET bits results in the full recovery of subsurface nanomechanical properties accompanied with only partial topography recovery, resulting in surface corrugations attributed to quenching. This precision sectioning and nanomechanical mapping approach could be applicable to a wide range of amorphous, nanocrystalline, and glass-forming materials for 3D nanomechanical mapping of amorphous-crystalline transitions.

  7. Structural morphology of amorphous conducting carbon film

    Indian Academy of Sciences (India)

    Unknown

    been found to be having a lot of technological applica- tions. The properties of these amorphous carbons sensi- tively depend on the relative concentration of sp3 and sp2 hybridized carbons. The resulting amorphous materials are variously referred to as tetrahedral amorphous carbon. (ta-C), amorphous carbon (a-C), ...

  8. Amorphous drugs and dosage forms

    DEFF Research Database (Denmark)

    Grohganz, Holger; Löbmann, K.; Priemel, P.

    2013-01-01

    The transformation to an amorphous form is one of the most promising approaches to address the low solubility of drug compounds, the latter being an increasing challenge in the development of new drug candidates. However, amorphous forms are high energy solids and tend to recry stallize. New...... formulation principles are needed to ensure the stability of amorphous drug forms. The formation of solid dispersions is still the most investigated approach, but additional approaches are desirable to overcome the shortcomings of solid dispersions. Spatial separation by either coating or the use of micro......-containers has shown potential to prevent or delay recrystallization. Another recent approach is the formation of co-amorphous mixtures between either two drugs or one drug and one low molecular weight excipient. Molecular interactions between the two molecules provide an energy barrier that has to be overcome...

  9. Field effect in GeTe thin films

    Energy Technology Data Exchange (ETDEWEB)

    Volker, Hanno; Schlockermann, Carl; Krebs, Daniel; Riedel, Joern; Wuttig, Matthias [RWTH Aachen University, I. Physikalisches Institut (IA), Aachen (Germany)

    2010-07-01

    Phase change memory is a promising candidate to replace common memory technologies such as Flash and DRAM due to its fast switching and excellent scaling perspectives. To improve memory density even further, it was proposed to combine the switchable resistor and the cell selection transistor in a single device. Current control by applying gate voltages has been demonstrated in the works of Yin et al. for Ge{sub 2}Sb{sub 2}Te{sub 5}. Recently, switching within a few nanoseconds has been demonstrated on a different material, GeTe. We therefore studied the field effect in thin films of amorphous GeTe. Dedicated transistor devices were prepared, and the transfer characteristics of these devices were measured as a function of temperature and film thickness. Furthermore, time-dependent behavior was observed and analyzed.

  10. Diamond amorphization in neutron irradiation

    International Nuclear Information System (INIS)

    Nikolaenko, V.A.; Gordeev, V.G.

    1996-01-01

    The paper presents the results on neutron irradiation of the diamond in a nuclear reactor. It is shown that the neutron irradiation stimulates the diamond transition to the amorphous state. At a temperature below 750 o K the time required for the diamond-graphite transition decreases with decreasing irradiation temperature. On the contrary, in irradiation at higher temperatures the time of diamond conversion into the amorphous state increases with decreasing but always remains shorter than in the absence of irradiation. (author)

  11. Anomalous magnetoresistance in amorphous metals

    International Nuclear Information System (INIS)

    Kuz'menko, V.M.; Vladychkin, A.N.; Mel'nikov, V.I.; Sudovtsev, A.I.

    1984-01-01

    The magnetoresistance of amorphous Bi, Ca, V and Yb films is investigated in fields up to 4 T at low temperatures. For all metals the magnetoresistance is positive, sharply decreases with growth of temperature and depends anomalously on the magnetic field strength. For amorphous superconductors the results agree satisfactorily with the theory of anomalous magnetoresistance in which allowance is made for scattering of electrons by the superconducting fluctuations

  12. Preparation and properties of Ge4Se96 glass

    Science.gov (United States)

    Xu, Junfeng; Sun, Guozhen; Liu, Zhenting; Wang, Yaling; Jian, Zengyun

    2018-03-01

    The chalcogenide glass Ge4Se96 was prepared by melt-quenched method. The characteristic temperatures (the strain point, annealing point, glass transition point, yielding point and soften point) were determined by thermal analysis. The result shows that the glass transition point is 52 °C; the average thermal expansion coefficient is ΔL/L0 = (0.0557∗T-1.7576)/1000. The specific heat of Ge4Se96 glass was measured by stepwise method. The difference in specific heat between amorphous structure and undercooled liquid was determined as ΔCp = 0.1812-5.20 × 10-4T-4.92 × 10-7T2 JK-1 g-1. Based on the result of ΔCp, the Gibbs energy and the entropy curves were calculated, and the Kauzmann temperature was determined as Tk = 233.5 K, which is between that for pure Se glass (216 K) and that for Ge7.4Se92.6 glass (250 K). It indicates that for Ge-Se glass with low Ge content, the Kauzmann temperature increases with increasing the content of Ge.

  13. Ion bipolar junction transistors.

    Science.gov (United States)

    Tybrandt, Klas; Larsson, Karin C; Richter-Dahlfors, Agneta; Berggren, Magnus

    2010-06-01

    Dynamic control of chemical microenvironments is essential for continued development in numerous fields of life sciences. Such control could be achieved with active chemical circuits for delivery of ions and biomolecules. As the basis for such circuitry, we report a solid-state ion bipolar junction transistor (IBJT) based on conducting polymers and thin films of anion- and cation-selective membranes. The IBJT is the ionic analogue to the conventional semiconductor BJT and is manufactured using standard microfabrication techniques. Transistor characteristics along with a model describing the principle of operation, in which an anionic base current amplifies a cationic collector current, are presented. By employing the IBJT as a bioelectronic circuit element for delivery of the neurotransmitter acetylcholine, its efficacy in modulating neuronal cell signaling is demonstrated.

  14. Indirect bipolar electrodeposition.

    Science.gov (United States)

    Loget, Gabriel; Roche, Jérome; Gianessi, Eugenio; Bouffier, Laurent; Kuhn, Alexander

    2012-12-12

    Based on the principles of bipolar electrochemistry, localized pH gradients are generated at the surface of conducting particles in solution. This allows the toposelective deposition of inorganic and organic polymer layers via a pH-triggered precipitation mechanism. Due to the intrinsic symmetry breaking of the process, the concept can be used to generate in a straightforward way Janus particles, with one section consisting of deposits obtained from non-electroactive precursors. These indirect electrodeposits, such as SiO(2), TiO(2), or electrophoretic paints, can be further used as an immobilization matrix for other species like dyes or nanoparticles, thus opening promising perspectives for the synthesis of a variety of bifunctional objects with a controlled shape.

  15. Genetics of bipolar disorder.

    Science.gov (United States)

    Kerner, Berit

    2014-01-01

    Bipolar disorder is a common, complex genetic disorder, but the mode of transmission remains to be discovered. Many researchers assume that common genomic variants carry some risk for manifesting the disease. The research community has celebrated the first genome-wide significant associations between common single nucleotide polymorphisms (SNPs) and bipolar disorder. Currently, attempts are under way to translate these findings into clinical practice, genetic counseling, and predictive testing. However, some experts remain cautious. After all, common variants explain only a very small percentage of the genetic risk, and functional consequences of the discovered SNPs are inconclusive. Furthermore, the associated SNPs are not disease specific, and the majority of individuals with a "risk" allele are healthy. On the other hand, population-based genome-wide studies in psychiatric disorders have rediscovered rare structural variants and mutations in genes, which were previously known to cause genetic syndromes and monogenic Mendelian disorders. In many Mendelian syndromes, psychiatric symptoms are prevalent. Although these conditions do not fit the classic description of any specific psychiatric disorder, they often show nonspecific psychiatric symptoms that cross diagnostic boundaries, including intellectual disability, behavioral abnormalities, mood disorders, anxiety disorders, attention deficit, impulse control deficit, and psychosis. Although testing for chromosomal disorders and monogenic Mendelian disorders is well established, testing for common variants is still controversial. The standard concept of genetic testing includes at least three broad criteria that need to be fulfilled before new genetic tests should be introduced: analytical validity, clinical validity, and clinical utility. These criteria are currently not fulfilled for common genomic variants in psychiatric disorders. Further work is clearly needed before genetic testing for common variants in

  16. Epitaxial growth of Ge-Sb-Te based phase change materials

    Energy Technology Data Exchange (ETDEWEB)

    Perumal, Karthick

    2013-07-30

    Ge-Sb-Te based phase change materials are considered as a prime candidate for optical and electrical data storage applications. With the application of an optical or electrical pulse, they can be reversibly switched between amorphous and crystalline state, thereby exhibiting large optical and electrical contrast between the two phases, which are then stored as information in the form of binary digits. Single crystalline growth is interesting from both the academic and industrial perspective, as ordered Ge-Sb-Te based metamaterials are known to exhibit switching at reduced energies. The present study deals with the epitaxial growth and analysis of Ge-Sb-Te based thin films. The first part of the thesis deals with the epitaxial growth of GeTe. Thin films of GeTe were grown on highly mismatched Si(111) and (001) substrates. On both the substrate orientations the film grows along [111] direction with an amorphous-to-crystalline transition observed during the initial stages of growth. The amorphous-to-crystalline transition was studied in-vivo using azimuthal reflection high-energy electron diffraction scans and grazing incidence X-ray diffraction. In the second part of the thesis epitaxy and characterization of Sb{sub 2}Te{sub 3} thin films are presented. The third part of the thesis deals with the epitaxy of ternary Ge-Sb-Te alloys. The composition of the films are shown to be highly dependent on growth temperatures and vary along the pseudobinary line from Sb{sub 2}Te{sub 3} to GeTe with increase in growth temperatures. A line-of-sight quadrupole mass spectrometer was used to reliably control the GeSbTe growth temperature. Growth was performed at different Ge, Sb, Te fluxes to study the compositional variation of the films. Incommensurate peaks are observed along the [111] direction by X-ray diffraction. The possibility of superstructural vacancy ordering along the [111] direction is discussed.

  17. Epitaxial growth of Ge-Sb-Te based phase change materials

    International Nuclear Information System (INIS)

    Perumal, Karthick

    2013-01-01

    Ge-Sb-Te based phase change materials are considered as a prime candidate for optical and electrical data storage applications. With the application of an optical or electrical pulse, they can be reversibly switched between amorphous and crystalline state, thereby exhibiting large optical and electrical contrast between the two phases, which are then stored as information in the form of binary digits. Single crystalline growth is interesting from both the academic and industrial perspective, as ordered Ge-Sb-Te based metamaterials are known to exhibit switching at reduced energies. The present study deals with the epitaxial growth and analysis of Ge-Sb-Te based thin films. The first part of the thesis deals with the epitaxial growth of GeTe. Thin films of GeTe were grown on highly mismatched Si(111) and (001) substrates. On both the substrate orientations the film grows along [111] direction with an amorphous-to-crystalline transition observed during the initial stages of growth. The amorphous-to-crystalline transition was studied in-vivo using azimuthal reflection high-energy electron diffraction scans and grazing incidence X-ray diffraction. In the second part of the thesis epitaxy and characterization of Sb 2 Te 3 thin films are presented. The third part of the thesis deals with the epitaxy of ternary Ge-Sb-Te alloys. The composition of the films are shown to be highly dependent on growth temperatures and vary along the pseudobinary line from Sb 2 Te 3 to GeTe with increase in growth temperatures. A line-of-sight quadrupole mass spectrometer was used to reliably control the GeSbTe growth temperature. Growth was performed at different Ge, Sb, Te fluxes to study the compositional variation of the films. Incommensurate peaks are observed along the [111] direction by X-ray diffraction. The possibility of superstructural vacancy ordering along the [111] direction is discussed.

  18. Applications of Si/SiGe heterostructures to CMOS devices

    International Nuclear Information System (INIS)

    Sidek, R.M.

    1999-03-01

    For more than two decades, advances in MOSFETs used in CMOS VLSI applications have been made through scaling to ever smaller dimensions for higher packing density, faster circuit speed and lower power dissipation. As scaling now approaches nanometer regime, the challenge for further scaling becomes greater in terms of technology as well as device reliability. This work presents an alternative approach whereby non-selectively grown Si/SiGe heterostructure system is used to improve device performance or to relax the technological challenge. SiGe is considered to be of great potential because of its promising properties and its compatibility with Si, the present mainstream material in microelectronics. The advantages of introducing strained SiGe in CMOS technology are examined through two types of device structure. A novel structure has been fabricated in which strained SiGe is incorporated in the source/drain of P-MOSFETs. Several advantages of the Si/SiGe source/drain P-MOSFETs over Si devices are experimentally, demonstrated for the first time. These include reduction in off-state leakage and punchthrough susceptibility, degradation of parasitic bipolar transistor (PBT) action, suppression of CMOS latchup and suppression of PBT-induced breakdown. The improvements due to the Si/SiGe heterojunction are supported by numerical simulations. The second device structure makes use of Si/SiGe heterostructure as a buried channel to enhance the hole mobility of P-MOSFETs. The increase in the hole mobility will benefit the circuit speed and device packing density. Novel fabrication processes have been developed to integrate non-selective Si/SiGe MBE layers into self-aligned PMOS and CMOS processes based on Si substrate. Low temperature processes have been employed including the use of low-pressure chemical vapor deposition oxide and plasma anodic oxide. Low field mobilities, μ 0 are extracted from the transfer characteristics, Id-Vg of SiGe channel P-MOSFETs with various Ge

  19. Modeling suicide in bipolar disorders.

    Science.gov (United States)

    Malhi, Gin S; Outhred, Tim; Das, Pritha; Morris, Grace; Hamilton, Amber; Mannie, Zola

    2018-02-19

    Suicide is a multicausal human behavior, with devastating and immensely distressing consequences. Its prevalence is estimated to be 20-30 times greater in patients with bipolar disorders than in the general population. The burden of suicide and its high prevalence in bipolar disorders make it imperative that our current understanding be improved to facilitate prediction of suicide and its prevention. In this review, we provide a new perspective on the process of suicide in bipolar disorder, in the form of a novel integrated model that is derived from extant knowledge and recent evidence. A literature search of articles on suicide in bipolar disorder was conducted in recognized databases such as Scopus, PubMed, and PsycINFO using the keywords "suicide", "suicide in bipolar disorders", "suicide process", "suicide risk", "neurobiology of suicide" and "suicide models". Bibliographies of identified articles were further scrutinized for papers and book chapters of relevance. Risk factors for suicide in bipolar disorders are well described, and provide a basis for a framework of epigenetic mechanisms, moderated by neurobiological substrates, neurocognitive functioning, and social inferences within the environment. Relevant models and theories include the diathesis-stress model, the bipolar model of suicide and the ideation-to-action models, the interpersonal theory of suicide, the integrated motivational-volitional model, and the three-step theory. Together, these models provide a basis for the generation of an integrated model that illuminates the suicidal process, from ideation to action. Suicide is complex, and it is evident that a multidimensional and integrated approach is required to reduce its prevalence. The proposed model exposes and provides access to components of the suicide process that are potentially measurable and may serve as novel and specific therapeutic targets for interventions in the context of bipolar disorder. Thus, this model is useful not only

  20. Hydrogenated amorphous silicon photonics

    Science.gov (United States)

    Narayanan, Karthik

    2011-12-01

    Silicon Photonics is quickly proving to be a suitable interconnect technology for meeting the future goals of on-chip bandwidth and low power requirements. However, it is not clear how silicon photonics will be integrated into CMOS chips, particularly microprocessors. The issue of integrating photonic circuits into electronic IC fabrication processes to achieve maximum flexibility and minimum complexity and cost is an important one. In order to minimize usage of chip real estate, it will be advantageous to integrate in three-dimensions. Hydrogenated amorphous silicon (a-Si:H) is emerging as a promising material for the 3-D integration of silicon photonics for on-chip optical interconnects. In addition, a-Si:H film can be deposited using CMOS compatible low temperature plasma-enhanced chemical vapor deposition (PECVD) process at any point in the fabrication process allowing maximum flexibility and minimal complexity. In this thesis, we demonstrate a-Si:H as a high performance alternate platform to crystalline silicon, enabling backend integration of optical interconnects in a hybrid photonic-electronic network-on-chip architecture. High quality passive devices are fabricated on a low-loss a-Si:H platform enabling wavelength division multiplexing schemes. We demonstrate a broadband all-optical modulation scheme based on free-carrier absorption effect, which can enable compact electro-optic modulators in a-Si:H. Furthermore, we comprehensively characterize the optical nonlinearities in a-Si:H and observe that a-Si:H exhibits enhanced nonlinearities as compared to crystalline silicon. Based on the enhanced nonlinearities, we demonstrate low-power four-wave mixing in a-Si:H waveguides enabling high speed all-optical devices in an a-Si:H platform. Finally, we demonstrate a novel data encoding scheme using thermal and all-optical tuning of silicon waveguides, increasing the spectral efficiency in an interconnect link.

  1. Bipolar redox behaviour, field-effect mobility and transistor switching of the low-molecular azo glass AZOPD.

    Science.gov (United States)

    Arlt, Michael; Scheffler, Ayna; Suske, Irina; Eschner, Michael; Saragi, Tobat P I; Salbeck, Josef; Fuhrmann-Lieker, Thomas

    2010-11-07

    We present electrochemical and spectroelectrochemical data for the bipolar azo compound N,N'-diphenyl-N,N'-bis[4-(phenylazo)phenyl]-4,4'diaminobiphenyl (AZOPD) demonstrating reversible bipolar redox behaviour with a bandgap of 2.1 eV. The reduced species formed upon two-electron transfer can be described as bis(radical anion) as was confirmed by comparison with a reference compound with only one azo chromophore. Hole and electron transport behaviour in amorphous films was demonstrated by the fabrication of organic field-effect transistors using gold and magnesium contacts, respectively. The transistors are sensitive to light due to E-Z photoisomerization.

  2. Maxwell rigidity and topological constraints in amorphous phase-change networks

    International Nuclear Information System (INIS)

    Micoulaut, M.; Otjacques, C.; Raty, J.-Y.; Bichara, C.

    2011-01-01

    By analyzing first-principles molecular-dynamics simulations of different telluride amorphous networks, we develop a method for the enumeration of radial and angular topological constraints, and show that the phase diagram of the most popular system Ge-Sb-Te can be split into two compositional elastic phases: a tellurium rich flexible phase and a stressed rigid phase that contains most of the materials used in phase-change applications. This sound atomic scale insight should open new avenues for the understanding of phase-change materials and other complex amorphous materials from the viewpoint of rigidity.

  3. Quetiapine monotherapy for bipolar depression

    Directory of Open Access Journals (Sweden)

    Michael E Thase

    2008-03-01

    Full Text Available Michael E ThaseDepartments of Psychiatry, University of Pennsylvania School of Medicine, Philadelphia, PA, USA; the Philadelphia Veterans Affairs Medical Center, Philadelphia, PA, USA; and the University of Pittsburgh Medical Center, Pittsburgh, PA, USAAbstract: Bipolar depression is more common, disabling, and difficult-to-treat than the manic and hypomanic phases that define bipolar disorder. Unlike the treatment of so-called “unipolar” depressions, antidepressants generally are not indicated as monotherapies for bipolar depressions and recent studies suggest that - even when used in combination with traditional mood stabilizers – antidepressants may have questionable value for bipolar depression. The current practice is that mood stabilizers are initiated first as monotherapies; however, the antidepressant efficacy of lithium and valproate is modest at best. Within this context the role of atypical antipsychotics is being evaluated. The combination of olanzapine and the antidepressant fluoxetine was the first treatment to receive regulatory approval in the US specifically for bipolar I depression. Quetiapine was the second medication to be approved for this indication, largely as the result of two pivotal trials known by the acronyms of BOLDER (BipOLar DEpRession I and II. Both studies demonstrated that two doses of quetiapine (300 mg and 600 mg given once daily at bedtime were significantly more effective than placebo, with no increased risk of patients switching into mania. Pooling the two studies, quetiapine was effective for both bipolar I and bipolar II depressions and for patients with (and without a history of rapid cycling. The two doses were comparably effective in both studies. Although the efficacy of quetiapine monotherapy has been established, much additional research is necessary. Further studies are needed to more fully investigate dose-response relationships and comparing quetiapine monotherapy to other mood stabilizers

  4. Optical transitions in Ge/SiGe multiple quantum wells with Ge-rich barriers

    Science.gov (United States)

    Bonfanti, M.; Grilli, E.; Guzzi, M.; Virgilio, M.; Grosso, G.; Chrastina, D.; Isella, G.; von Känel, H.; Neels, A.

    2008-07-01

    Direct-gap and indirect-gap transitions in strain-compensated Ge/SiGe multiple quantum wells with Ge-rich SiGe barriers have been studied by optical transmission spectroscopy and photoluminescence experiments. An sp3d5s∗ tight-binding model has been adopted to interpret the experimental results. Photoluminescence spectra and their comparison with theoretical calculations prove the existence of type-I band alignment in compressively strained Ge quantum wells grown on relaxed Ge-rich SiGe buffers. The high quality of the transmission spectra opens up other perspectives for application of these structures in near-infrared optical modulators.

  5. Structural, thermal, and photoacoustic study of nanocrystalline Cr{sub 3}Ge produced by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Prates, P. B.; Maliska, A. M.; Ferreira, A. S. [Departamento de Engenharia Mecânica, Universidade Federal de Santa Catarina, Campus Universitário Trindade, S/N, C.P. 476, 88040-900 Florianópolis, Santa Catarina (Brazil); Poffo, C. M. [Universidade Federal de Santa Catarina, Campus de Araranguá, 88900-000 Araranguá, Santa Catarina (Brazil); Borges, Z. V. [Departamento de Física, Universidade Federal do Amazonas, 3000 Japiim, 69077-000 Manaus, Amazonas (Brazil); Lima, J. C. de, E-mail: fsc1jcd@fisica.ufsc.br [Departamento de Física, Universidade Federal de Santa Catarina, Campus Universitário Trindade, S/N, C.P. 476, 88040-900 Florianópolis, Santa Catarina (Brazil); Biasi, R. S. de [Seção de Engenharia Mecânica e de Materiais, Instituto Militar de Engenharia, 22290-270 Rio de Janeiro (Brazil)

    2015-10-21

    A thermodynamic analysis of the Cr-Ge system suggested that it was possible to produce a nanostructured Cr{sub 3}Ge phase by mechanical alloying. The same analysis showed that, due to low activation energies, Cr-poor crystalline and/or amorphous alloy could also be formed. In fact, when the experiment was performed, Cr{sub 11}Ge{sub 19} and amorphous phases were present for small milling times. For milling times larger than 15 h these additional phases decomposed and only the nanostructured Cr{sub 3}Ge phase remained up to the highest milling time used (32 h). From the differential scanning calorimetry measurements, the Avrami exponent n was obtained, indicating that the nucleation and growth of the nanostructured Cr{sub 3}Ge phase may be restricted to one or two dimensions, where the Cr and Ge atoms diffuse along the surface and grain boundaries. In addition, contributions from three-dimensional diffusion with a constant nucleation rate may be present. The thermal diffusivity of the nanostructured Cr{sub 3}Ge phase was determined by photoacoustic absorption spectroscopy measurements.

  6. Degradation of SiGe devices by proton irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Ohyama, Hidenori; Hayama, Kiyoteru [Kumamoto National Coll. of Technology, Nishigoshi (Japan); Vanhellemont, J.; Takami, Yasukiyo; Sunaga, Hiromi; Nashiyama, Isamu; Uwatoko, Yoshiya; Poortmans, J.; Caymax, M.

    1997-03-01

    The degradation and recovery behavior of strained Si{sub 1-x}Ge{sub x} diodes and heterojunction bipolar transistors (HBTs) by irradiated by protons are studied. The degradation of device performance and the generation of lattice defects are reported as a function of fluence and germanium content and also compared extensively with previous results obtained on electron and neutron irradiated devices. In order to study the recovery behavior of the irradiated devices, isochronal annealing is performed. The radiation source dependence of the degradation is discussed taking into account the number of knock-on atoms and the nonionizing energy loss (NIEL). (author)

  7. Integrated neurobiology of bipolar disorder

    Directory of Open Access Journals (Sweden)

    Vladimir eMaletic

    2014-08-01

    Full Text Available From a neurobiological perspective there is no such thing as bipolar disorder. Rather, it is almost certainly the case that many somewhat similar, but subtly different, pathological conditions produce a disease state that we currently diagnose as bipolarity. This heterogeneity—reflected in the lack of synergy between our current diagnostic schema and our rapidly advancing scientific understanding of the condition—limits attempts to articulate an integrated perspective on bipolar disorder. However, despite these challenges, scientific findings in recent years are beginning to offer a provisional unified field theory of the disease. This theory sees bipolar disorder as a suite of related neurodevelopmental conditions with interconnected functional abnormalities that often appear early in life and worsen over time. In addition to accelerated loss of volume in brain areas known to be essential for mood regulation and cognitive function, consistent findings have emerged at a cellular level, providing evidence that bipolar disorder is reliably associated with dysregulation of glial-neuronal interactions. Among these glial elements are microglia—the brain’s primary immune elements, which appear to be overactive in the context of bipolarity. Multiple studies now indicate that inflammation is also increased in the periphery of the body in both the depressive and manic phases of the illness, with at least some return to normality in the euthymic state. These findings are consistent with changes in the HPA axis, which are known to drive inflammatory activation. In summary, the very fact that no single gene, pathway or brain abnormality is likely to ever account for the condition is itself an extremely important first step in better articulating an integrated perspective on both its ontological status and pathogenesis. Whether this perspective will translate into the discovery of innumerable more homogeneous forms of bipolarity is one of the great

  8. Experimental DC extraction of the thermal resistance of bipolar transistors taking into account the Early effect

    Science.gov (United States)

    d'Alessandro, Vincenzo

    2017-01-01

    This paper presents three methods to experimentally extract the thermal resistance of bipolar transistors taking into account the Early effect. The approaches are improved variants of recently-proposed techniques relying on common-base DC measurements. The accuracy is numerically verified by making use of a compact model calibrated on I-V characteristics of state-of-the-art SOG BJTs and SiGe:C HBTs.

  9. Verification of the Simultaneous Local Extraction Method of Base and Thermal Resistance of Bipolar Transistors

    OpenAIRE

    Robert Setekera; Luuk Tiemeijer; Ramses van der Toorn

    2014-01-01

    In this paper an extensive verification of the extraction method (published earlier) that consistently accounts for self-heating and Early effect to accurately extract both base and thermal resistance of bipolar junction transistors is presented. The method verification is demonstrated on advanced RF SiGe HBTs were the extracted results for the thermal resistance are compared with those from another published method that ignores the effect of Early effect on internal base...

  10. A zero density change phase change memory material: GeTe-O structural characteristics upon crystallisation.

    Science.gov (United States)

    Zhou, Xilin; Dong, Weiling; Zhang, Hao; Simpson, Robert E

    2015-06-11

    Oxygen-doped germanium telluride phase change materials are proposed for high temperature applications. Up to 8 at.% oxygen is readily incorporated into GeTe, causing an increased crystallisation temperature and activation energy. The rhombohedral structure of the GeTe crystal is preserved in the oxygen doped films. For higher oxygen concentrations the material is found to phase separate into GeO2 and TeO2, which inhibits the technologically useful abrupt change in properties. Increasing the oxygen content in GeTe-O reduces the difference in film thickness and mass density between the amorphous and crystalline states. For oxygen concentrations between 5 and 6 at.%, the amorphous material and the crystalline material have the same density. Above 6 at.% O doping, crystallisation exhibits an anomalous density change, where the volume of the crystalline state is larger than that of the amorphous. The high thermal stability and zero-density change characteristic of Oxygen-incorporated GeTe, is recommended for efficient and low stress phase change memory devices that may operate at elevated temperatures.

  11. Structure and Spatial Distribution of Ge Nanocrystals Subjected to Fast Neutron Irradiation

    Directory of Open Access Journals (Sweden)

    Alexander N. Ionov

    2011-07-01

    Full Text Available The influence of fast neutron irradiation on the structure and spatial distribution of Ge nanocrystals (NC embedded in an amorphous SiO2 matrix has been studied. The investigation was conducted by means of laser Raman Scattering (RS, High Resolution Transmission Electron Microscopy (HR-TEM and X-ray photoelectron spectroscopy (XPS. The irradiation of Ge- NC samples by a high dose of fast neutrons lead to a partial destruction of the nanocrystals. Full reconstruction of crystallinity was achieved after annealing the radiation damage at 8000C, which resulted in full restoration of the RS spectrum. HR-TEM images show, however, that the spatial distributions of Ge-NC changed as a result of irradiation and annealing. A sharp decrease in NC distribution towards the SiO2 surface has been observed. This was accompanied by XPS detection of Ge oxides and elemental Ge within both the surface and subsurface region.

  12. The Chemically-Specific Structure of an Amorphous Molybdenum Germanium Alloy by Anomalous X-ray Scattering

    Energy Technology Data Exchange (ETDEWEB)

    Ishii, H. A.

    2002-06-11

    Since its inception in the late 1970s, anomalous x-ray scattering (AXS) has been employed for chemically-specific structure determination in a wide variety of noncrystalline materials. These studies have successfully produced differential distribution functions (DDFs) which provide information about the compositionally-averaged environment of a specific atomic species in the sample. Despite the wide success in obtaining DDFs, there are very few examples of successful extraction of the fully-chemically-specific partial pair distribution functions (PPDFs), the most detailed description of an amorphous sample possible by x-ray scattering. Extracting the PPDFs is notoriously difficult since the matrix equation involved is ill-conditioned and thus extremely sensitive to errors present in the experimental quantities that enter the equation. Instead of addressing this sensitivity by modifying the data through mathematical methods, sources of error have been removed experimentally: A focusing analyzer crystal was combined with a position-sensitive linear detector to experimentally eliminate unwanted inelastic scattering intensity over most of the reciprocal space range probed. This instrumentation has been used in data collection for the extraction of PPDFs from amorphous (a)-MoGe{sub 3}. This composition arises as a phase separation endpoint in the Ge-rich region of the vapor-deposited Mo-Ge amorphous alloy system but is not present at equilibrium. Since the first Ge-rich compound in the Mo-Ge equilibrium system is MoGe{sub 2}, previous workers have speculated that perhaps a unique MoGe{sub 3} compound exists in the amorphous system. Rather than indicating a distinct MoGe{sub 3} compound with definitive local structure, however, the coordination results are more consistent with a densely-packed alloy having a wide range of solid solubility. Significant improvement in the quality and reliability of experimental PPDFs from a-MoGe{sub 3} by AXS has been achieved solely

  13. A SiGe BiCMOS double-balanced mixer with active balun for X-band Doppler radar

    DEFF Research Database (Denmark)

    Michaelsen, Rasmus S.; Johansen, Tom K.; Tamborg, Kjeld M.

    2015-01-01

    In this paper, we present an X-band doublebalanced mixer in SiGe BiCMOS technology. The mixer core consists of a LO Matched quad diode ring using diode-connected Heterojunction Bipolar Transistors (HBTs). The mixer is integrated with a low-noise, high-linearity active balun on the RF port...

  14. [Genetics of bipolar disorder].

    Science.gov (United States)

    Budde, M; Forstner, A J; Adorjan, K; Schaupp, S K; Nöthen, M M; Schulze, T G

    2017-07-01

    Bipolar disorder (BD) has a multifactorial etiology. Its development is influenced by genetic as well as environmental factors. Large genome-wide association studies (GWAS), in which genetic risk allelic variants for the disorder could be replicated for the first time, marked the breakthrough in the identification of the responsible risk genes. In addition to these common genetic variants with moderate effects identified by GWAS, rare variants with a higher penetrance are expected to play a role in disease development. The results of recent studies suggest that copy number variants might contribute to BD development, although to a lesser extent than in other psychiatric disorders, such as schizophrenia or autism. Results from the initial next generation sequencing studies indicate an enrichment of rare variants in pathways and genes that were previously found to be associated with BD. In the field of pharmacogenetics, a risk gene that influences the individual variance in the response to lithium treatment was identified for the first time in a recent large international GWAS. Currently the reported risk alleles do not sufficiently explain the phenotypic variance to be used for individual prediction of disease risk, disease course or response to medication. Future genetic research will provide important insights into the biological basis of BD by the identification of additional genes associated with BD. This knowledge of genetics will help identify potential etiological subgroups as well as cross-diagnostic disease mechanisms.

  15. Nanostructures having crystalline and amorphous phases

    Science.gov (United States)

    Mao, Samuel S; Chen, Xiaobo

    2015-04-28

    The present invention includes a nanostructure, a method of making thereof, and a method of photocatalysis. In one embodiment, the nanostructure includes a crystalline phase and an amorphous phase in contact with the crystalline phase. Each of the crystalline and amorphous phases has at least one dimension on a nanometer scale. In another embodiment, the nanostructure includes a nanoparticle comprising a crystalline phase and an amorphous phase. The amorphous phase is in a selected amount. In another embodiment, the nanostructure includes crystalline titanium dioxide and amorphous titanium dioxide in contact with the crystalline titanium dioxide. Each of the crystalline and amorphous titanium dioxide has at least one dimension on a nanometer scale.

  16. Fundamentals of amorphous solids structure and properties

    CERN Document Server

    Stachurski, Zbigniew H

    2014-01-01

    Long awaited, this textbook fills the gap for convincing concepts to describe amorphous solids. Adopting a unique approach, the author develops a framework that lays the foundations for a theory of amorphousness. He unravels the scientific mysteries surrounding the topic, replacing rather vague notions of amorphous materials as disordered crystalline solids with the well-founded concept of ideal amorphous solids. A classification of amorphous materials into inorganic glasses, organic glasses, glassy metallic alloys, and thin films sets the scene for the development of the model of ideal amorph

  17. Thin-film amorphous silicon germanium solar cells with p-and n-type hydrogenated silicon oxide layers

    NARCIS (Netherlands)

    Si, F.T.; Isabella, O.; Zeman, M.

    2017-01-01

    Mixed-phase hydrogenated silicon oxide (SiOx:H) is applied to thin-film hydrogenated amorphous silicon germanium (a-SiGe:H) solar cells serving as both p-doped and n-doped layers. The bandgap of p-SiOx:H is adjusted to achieve a highly-transparent window layer while also providing a strong electric

  18. Bipolar Disorder in Children and Teens

    Science.gov (United States)

    ... I do? Share Bipolar Disorder in Children and Teens Download PDF Download ePub Order a free hardcopy ... Think about death or suicide Can children and teens with bipolar disorder have other problems? Young people ...

  19. Exercising control over bipolar disorder.

    Science.gov (United States)

    Malhi, Gin S; Byrow, Yulisha

    2016-11-01

    Following extensive research exercise has emerged as an effective treatment for major depressive disorder, and it is now a recognised therapy alongside other interventions. In contrast, there is a paucity of research examining the therapeutic effects of exercise for those with bipolar disorder. Given that dysfunctional reward processing is central to bipolar disorder, research suggests that exercise can perhaps be framed as a reward-related event that may have the potential to precipitate a manic episode. The behavioural activation system (BAS) is a neurobehavioural system that is associated with responding to reward and provides an appropriate framework to theoretically examine and better understand the effects of exercise treatment on bipolar disorder. This article discusses recent research findings and provides an overview of the extant literature related to the neurobiological underpinnings of BAS and exercise as they relate to bipolar disorder. This is important clinically because depending on mood state in bipolar disorder, we postulate that exercise could be either beneficial or deleterious with positive or negative effects on the illness. Clearly, this complicates the evaluation of exercise as a potential treatment in terms of identifying its optimal characteristics in this population. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  20. Magnetic properties of crystalline and amorphous phase-change materials doped with 3d impurities.

    Science.gov (United States)

    Zhang, Wei; Ronneberger, Ider; Li, Yan; Mazzarello, Riccardo

    2012-08-22

    First-principles study of the structural and magnetic properties of cubic and amorphous phase-change materials doped with 3d impurities. We find that Co- and Ni-doped Ge(2) Sb(2) Te(5) is non-magnetic, whereas Cr- and Mn-doped Ge(2) Sb(2) Te(5) is magnetic and exhibits a significant magnetic contrast between the two phases in the ferromagnetic configuration. These results are explained in terms of differences in local structure and hybridization of the impurity d-orbitals with the host states. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Role of activation energy in resistance drift of amorphous phase change materials

    OpenAIRE

    Wimmer, Martin; Kaes, Matthias; Dellen, Christian; Salinga, Martin

    2014-01-01

    The time evolution of the resistance of amorphous thin films of the phase change materials Ge2Sb2Te5, GeTe and AgIn-Sb2Te is measured during annealing at T = 80°C. The annealing process is interrupted by several fast temperature dips to determine the changing temperature dependence of the resistance. This procedure enables us to identify to what extent the resistance increase over time can be traced back to an increase in activation energy EA or to a rise of the prefactor R*. We observe that,...

  2. Imunologia do transtorno bipolar Immunology of bipolar disorder

    Directory of Open Access Journals (Sweden)

    Izabela Guimarães Barbosa

    2009-01-01

    Full Text Available OBJETIVO: Pesquisas recentes têm implicado fatores imunes na patogênese de diversos transtornos neuropsiquiátricos. O objetivo do presente trabalho é revisar os trabalhos que investigaram a associação entre transtorno bipolar e alterações em parâmetros imunes. MÉTODOS: Artigos que incluíam as palavras-chave: "bipolar disorder", "mania", "immunology", "cytokines", "chemokines", "interleukins", "interferon" e "tumor necrosis factor" foram selecionados em uma revisão sistemática da literatura. As bases de dados avaliadas foram MedLine e Scopus, entre os anos de 1980 e 2008. RESULTADOS: Foram identificados 28 trabalhos que estudaram alterações imunes em pacientes com transtorno bipolar. Seis artigos investigaram genes relacionados à resposta imune; cinco, autoanticorpos; quatro, populações leucocitárias; 13, citocinas e/ou moléculas relacionadas à resposta imune e seis, leucócitos de pacientes in vitro. CONCLUSÕES: Embora haja evidências na literatura correlacionando o transtorno bipolar a alterações imunes, os dados não são conclusivos. O transtorno bipolar parece estar associado a níveis mais elevados de autoanticorpos circulantes, assim como à tendência à ativação imune com produção de citocinas pró-inflamatórias e redução de parâmetros anti-inflamatórios.OBJECTIVE: Emerging research has implicated immune factors in the pathogenesis of a variety of neuropsychiatric disorders. The objective of the present paper is to review the studies that investigated the association between bipolar disorder and immune parameters. METHODS: Papers that included the keywords "bipolar to disorder", "mania", "immunology", "cytokines", "chemokines", "interleukins", "interferon" and "tumor necrosis factor" were selected in a systematic review of the literature. The evaluated databases were MedLine and Scopus in the period between 1980 and 2008. RESULTS: Twenty eight works were found. Six studies investigated immune response

  3. Synchrotron applications of an amorphous silicon flat-panel detector

    International Nuclear Information System (INIS)

    Lee, J. H.; Can Aydiner, C.; Almer, J.; Bernier, J.; Chapman, K. W.; Chupas, P. J.; Haeffner, D.; Kump, K.; Lee, P. L.; Lienert, U.; Miceli, A.; Vera, G.; LANL; GE Healthcare

    2008-01-01

    A GE Revolution 41RT flat-panel detector (GE 41RT) from GE Healthcare (GE) has been in operation at the Advanced Photon Source for over two years. The detector has an active area of 41 cm x 41 cm with 200 (micro)m x 200 (micro)m pixel size. The nominal working photon energy is around 80 keV. The physical set-up and utility software of the detector system are discussed in this article. The linearity of the detector response was measured at 80.7 keV. The memory effect of the detector element, called lag, was also measured at different exposure times and gain settings. The modulation transfer function was measured in terms of the line-spread function using a 25 (micro)m x 1 cm tungsten slit. The background (dark) signal, the signal that the detector will carry without exposure to X-rays, was measured at three different gain settings and with exposure times of 1 ms to 15 s. The radial geometric flatness of the sensor panel was measured using the diffraction pattern from a CeO 2 powder standard. The large active area and fast data-capturing rate, i.e. 8 frames s -1 in radiography mode, 30 frames s -1 in fluoroscopy mode, make the GE 41RT one of a kind and very versatile in synchrotron diffraction. The loading behavior of a Cu/Nb multilayer material is used to demonstrate the use of the detector in a strain-stress experiment. Data from the measurement of various samples, amorphous SiO 2 in particular, are presented to show the detector effectiveness in pair distribution function measurements

  4. Ferromagnetism modulation by phase change in Mn-doped GeTe chalcogenide magnetic materials

    Energy Technology Data Exchange (ETDEWEB)

    Adam, Adam Abdalla Elbashir [Huazhong University of Science and Technology, School of Optical and Electronic Information, Wuhan (China); Wuhan National Laboratory for Optoelectronics, Wuhan (China); Alneelain University, Faculty of Science and Technology, Khartoum (Sudan); Cheng, Xiaomin; Guan, Xiawei; Miao, Xiangshui [Huazhong University of Science and Technology, School of Optical and Electronic Information, Wuhan (China); Wuhan National Laboratory for Optoelectronics, Wuhan (China)

    2014-12-15

    In this work, an effective method to modulate the ferromagnetic properties of Mn-doped GeTe chalcogenide-based phase change materials is presented. The microstructure of the phase change magnetic material Ge{sub 1-x} Mn{sub x} Te thin films was studied. The X-ray diffraction results demonstrate that the as-deposited films are amorphous, and the crystalline films are formed after annealing at 350 C for 10 min. Crystallographic structure investigation shows the existence of some secondary magnetic phases. The lattice parameters of Ge{sub 1-x} Mn{sub x} Te (x = 0.04, 0.12 and 0.15) thin films are found to be slightly different with changes of Mn compositions. The structural analysis clearly indicates that all the films have a stable rhombohedral face-centered cubic polycrystalline structure. The magnetic properties of the amorphous and crystalline Ge{sub 0.96}Mn{sub 0.04}Te were investigated. The measurements of magnetization (M) as a function of the magnetic field (H) show that both amorphous and crystalline phases of Ge{sub 0.96}Mn{sub 0.04}Te thin film are ferromagnetic and there is drastic variation between amorphous and crystalline states. The temperature (T) dependence of magnetizations at zero field cooling (ZFC) and field cooling (FC) conditions of the crystalline Ge{sub 0.96}Mn{sub 0.04}Te thin film under different applied magnetic fields were performed. The measured data at 100 and 300 Oe applied magnetic fields show large bifurcations in the ZFC and FC curves while on the 5,000 Oe magnetic field there is no deviation. (orig.)

  5. Electrodeposition at room temperature of amorphous silicon and germanium nanowires in ionic liquid

    Energy Technology Data Exchange (ETDEWEB)

    Martineau, F; Namur, K; Mallet, J; Delavoie, F; Troyon, M; Molinari, M [Laboratoire de Microscopies et d' Etude de Nanostructures (LMEN EA3799), Universite de Reims Champagne Ardennes (URCA), Reims Cedex 2 (France); Endres, F, E-mail: michael.molinari@univ-reims.fr [Institute of Particle Technology, Chair of Interface Processes, Clausthal University of Technology, D-36678 Clausthal-Zellerfeld (Germany)

    2009-11-15

    The electrodeposition at room temperature of silicon and germanium nanowires from the air- and water-stable ionic liquid 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (P{sub 1,4}) containing SiCl{sub 4} as Si source or GeCl{sub 4} as Ge source is investigated by cyclic voltammetry. By using nanoporous polycarbonate membranes as templates, it is possible to reproducibly grow pure silicon and germanium nanowires of different diameters. The nanowires are composed of pure amorphous silicon or germanium. The nanowires have homogeneous cylindrical shape with a roughness of a few nanometres on the wire surfaces. The nanowires' diameters and lengths well match with the initial membrane characteristics. Preliminary photoluminescence experiments exhibit strong emission in the near infrared for the amorphous silicon nanowires.

  6. Ion-beam doping of amorphous silicon with germanium isovalent impurity

    International Nuclear Information System (INIS)

    Khokhlov, A.F.; Mashin, A.I.; Ershov, A.V.; Mashin, N.I.; Ignat'eva, E.A.

    1988-01-01

    Experimental data on ion-beam doping of amorphous silicon containing minor germanium additions by donor and acceptor impurity are presented. Doping of a-Si:Ge films as well as of a-Si layers was performed by implantation of 40 keV energy B + ions or 120 keV energy phosphorus by doses from 3.2x10 13 up to 1.3x10 17 cm -2 . Ion current density did not exceed 1 μA/cm 2 . Radiation defect annealing was performed at 400 deg C temperature during 30 min. Temperature dependences of conductivity in the region of 160-500 K were studied. It is shown that a-Si:Ge is like hydrogenized amorphous silicon in relation to doping

  7. Mathematical models of bipolar disorder

    Science.gov (United States)

    Daugherty, Darryl; Roque-Urrea, Tairi; Urrea-Roque, John; Troyer, Jessica; Wirkus, Stephen; Porter, Mason A.

    2009-07-01

    We use limit cycle oscillators to model bipolar II disorder, which is characterized by alternating hypomanic and depressive episodes and afflicts about 1% of the United States adult population. We consider two non-linear oscillator models of a single bipolar patient. In both frameworks, we begin with an untreated individual and examine the mathematical effects and resulting biological consequences of treatment. We also briefly consider the dynamics of interacting bipolar II individuals using weakly-coupled, weakly-damped harmonic oscillators. We discuss how the proposed models can be used as a framework for refined models that incorporate additional biological data. We conclude with a discussion of possible generalizations of our work, as there are several biologically-motivated extensions that can be readily incorporated into the series of models presented here.

  8. Control of interfacial properties of Pr-oxide/Ge gate stack structure by introduction of nitrogen

    Science.gov (United States)

    Kato, Kimihiko; Kondo, Hiroki; Sakashita, Mitsuo; Nakatsuka, Osamu; Zaima, Shigeaki

    2011-06-01

    We have demonstrated the control of interfacial properties of Pr-oxide/Ge gate stack structure by the introduction of nitrogen. From C- V characteristics of Al/Pr-oxide/Ge 3N 4/Ge MOS capacitors, the interface state density decreases without the change of the accumulation capacitance after annealing. The TEM and TED measurements reveal that the crystallization of Pr-oxide is enhanced with annealing and the columnar structure of cubic-Pr 2O 3 is formed after annealing. From the depth profiles measured using XPS with Ar sputtering for the Pr-oxide/Ge 3N 4/Ge stack structure, the increase in the Ge component is not observed in a Pr-oxide film and near the interface between a Pr-oxide film and a Ge substrate. In addition, the N component segregates near the interface region, amorphous Pr-oxynitride (PrON) is formed at the interface. As a result, Pr-oxide/PrON/Ge stacked structure without the Ge-oxynitride interlayer is formed.

  9. Amorphous nanoparticles — Experiments and computer simulations

    International Nuclear Information System (INIS)

    Hoang, Vo Van; Ganguli, Dibyendu

    2012-01-01

    The data obtained by both experiments and computer simulations concerning the amorphous nanoparticles for decades including methods of synthesis, characterization, structural properties, atomic mechanism of a glass formation in nanoparticles, crystallization of the amorphous nanoparticles, physico-chemical properties (i.e. catalytic, optical, thermodynamic, magnetic, bioactivity and other properties) and various applications in science and technology have been reviewed. Amorphous nanoparticles coated with different surfactants are also reviewed as an extension in this direction. Much attention is paid to the pressure-induced polyamorphism of the amorphous nanoparticles or amorphization of the nanocrystalline counterparts. We also introduce here nanocomposites and nanofluids containing amorphous nanoparticles. Overall, amorphous nanoparticles exhibit a disordered structure different from that of corresponding bulks or from that of the nanocrystalline counterparts. Therefore, amorphous nanoparticles can have unique physico-chemical properties differed from those of the crystalline counterparts leading to their potential applications in science and technology.

  10. Transcultural aspects of bipolar disorder

    OpenAIRE

    Sanches, Marsal; Jorge, Miguel Roberto

    2004-01-01

    Considerando-se que existem diferenças importantes na maneira como as emoções são vivenciadas e expressas em diferentes culturas, a apresentação e o manejo do transtorno afetivo bipolar sofrem influência de fatores culturais. O presente artigo realiza uma breve revisão da evidência referente aos aspectos transculturais do transtorno bipolar.Cultural variations in the expression of emotions have been described. Consequently, there are cross-cultural influences on the diagnosis and management o...

  11. Model for amorphous aggregation processes

    Science.gov (United States)

    Stranks, Samuel D.; Ecroyd, Heath; van Sluyter, Steven; Waters, Elizabeth J.; Carver, John A.; von Smekal, Lorenz

    2009-11-01

    The amorphous aggregation of proteins is associated with many phenomena, ranging from the formation of protein wine haze to the development of cataract in the eye lens and the precipitation of recombinant proteins during their expression and purification. While much literature exists describing models for linear protein aggregation, such as amyloid fibril formation, there are few reports of models which address amorphous aggregation. Here, we propose a model to describe the amorphous aggregation of proteins which is also more widely applicable to other situations where a similar process occurs, such as in the formation of colloids and nanoclusters. As first applications of the model, we have tested it against experimental turbidimetry data of three proteins relevant to the wine industry and biochemistry, namely, thaumatin, a thaumatinlike protein, and α -lactalbumin. The model is very robust and describes amorphous experimental data to a high degree of accuracy. Details about the aggregation process, such as shape parameters of the aggregates and rate constants, can also be extracted.

  12. Amorphous metal matrix composite ribbons

    International Nuclear Information System (INIS)

    Barczy, P.; Szigeti, F.

    1998-01-01

    Composite ribbons with amorphous matrix and ceramic (SiC, WC, MoB) particles were produced by modified planar melt flow casting methods. Weldability, abrasive wear and wood sanding examinations were carried out in order to find optimal material and technology for elevated wear resistance and sanding durability. The correlation between structure and composite properties is discussed. (author)

  13. Atomistic Models of Amorphous Semiconductors

    NARCIS (Netherlands)

    Jarolimek, K.

    2011-01-01

    Crystalline silicon is probably the best studied material, widely used by the semiconductor industry. The subject of this thesis is an intriguing form of this element namely amorphous silicon. It can contain a varying amount of hydrogen and is denoted as a-Si:H. It completely lacks the neat long

  14. Fracture Phenomena in Amorphous Selenium

    DEFF Research Database (Denmark)

    Lindegaard-Andersen, Asger; Dahle, Birgit

    1966-01-01

    Fracture surfaces of amorphous selenium broken in flexure at room temperature have been studied. The fracture velocity was found to vary in different regions of the fracture surface. Peculiar features were observed in a transition zone between fast and slower fracture. In this zone cleavage steps...

  15. Electronic monitoring in bipolar disorder.

    Science.gov (United States)

    Faurholt-Jepsen, Maria

    2018-03-01

    Major reasons for the insufficient effects of current treatment options in bipolar disorder include delayed intervention for prodromal depressive and manic symptoms and decreased adherence to psychopharmacological treatment. The reliance on subjective information and clinical evaluations when diagnosing and assessing the severity of depressive and manic symptoms calls for less biased and more objective markers. By using electronic devices, fine-grained data on complex psychopathological aspects of bipolar disorder can be evaluated unobtrusively over the long term. Moreover, electronic data could possibly represent candidate markers of diagnosis and illness activity in bipolar disorder and allow for early and individualized intervention for prodromal symptoms outside clinical settings. 
The present dissertation concerns the use of electronic monitoring as a marker and treatment intervention in bipolar disorder and investigated the scientific literature and body of evidence within the area, which includes ten original study reports and two systematic reviews, one of which included a meta-analysis, conducted by the author of the dissertation. 
Taken together, the literature presented in this dissertation illustrates that 1) smartphone-based electronic self-monitoring of mood seems to reflect clinically assessed depressive and manic symptoms and enables the long-term characterization of mood

instability in bipolar disorder; 2) preliminary results suggest that smartphone-based automatically generated data (e.g. the number of text messages sent/day; the number of incoming and outgoing calls/day; the number of changes in cell tower IDs/day; and voice features) seem to reflect clinically assessed depressive and manic symptoms in bipolar disorder; 3) smartphone-based electronic self-monitoring had no effects on the severity of depressive and manic symptoms in bipolar disorder, according to a randomized controlled trial; and 4) electronic monitoring of psychomotor

  16. Ion-beam induced structure modifications in amorphous germanium; Ionenstrahlinduzierte Strukturmodifikationen in amorphem Germanium

    Energy Technology Data Exchange (ETDEWEB)

    Steinbach, Tobias

    2012-05-03

    Object of the present thesis was the systematic study of ion-beam induced structure modifications in amorphous germanium (a-Ge) layers due to low- (LEI) and high-energetic (SHI) ion irradiation. The LEI irradiation of crystalline Ge (c-Ge) effects because the dominating nuclear scattering of the ions on the solid-state atoms the formation of a homogeneous a-Ge Layer. Directly on the surface for fluences of two orders of magnitude above the amorphization fluence the formation of stable cavities independently on the irradiation conditions was observed. For the first time for the ion-beam induced cavity formation respectively for the steady expansion of the porous layer forming with growing fluence a linear dependence on the energy {epsilon}{sub n} deposed in nuclear processes was detected. Furthermore the formation of buried cavities was observed, which shows a dependence on the type of ions. While in the c-Ge samples in the range of the high electronic energy deposition no radiation defects, cavities, or plastic deformations were observed, the high electronic energy transfer in the 3.1 {mu}m thick pre-amorphized a-Ge surface layers leads to the formation of randomly distributed cavities. Basing on the linear connection between cavity-induced vertical volume expansion and the fluence determined for different energy transfers for the first time a material-specific threshold value of {epsilon}{sub e}{sup HRF}=(10.5{+-}1.0) kev nm{sup -1} was determined, above which the ion-beam induced cavity formation in a-Ge sets on. The anisotropic plastic deformation of th a-Ge layer superposed at inclined SHI irradiation on the cavity formation was very well described by an equation derived from the viscoelastic Maxwell model, but modified under regardment of the experimental results. The positive deformation yields determined thereby exhibit above a threshold value for the ion-beam induced plastic deformation {epsilon}{sub e}{sup S{sub a}}=(12{+-}2) keV nm{sup -1} for the first

  17. Epidemiologia do transtorno bipolar Epidemiology of bipolar disorders

    Directory of Open Access Journals (Sweden)

    Maurício Silva de Lima

    2005-01-01

    Full Text Available A formulação de políticas em saúde mental depende essencialmente de informações a respeito da freqüência e distribuição dos transtornos mentais. Nas últimas duas décadas, pesquisas de base populacional em epidemiologia psiquiátrica têm sido conduzidas, gerando informações detalhadas sobre freqüência, fatores de risco, incapacidade social e utilização de serviços de saúde. Neste artigo, dados sobre a epidemiologia do transtorno bipolar (TB são discutidos, a partir de resultados de recentes pesquisas populacionais: o estudo da Área de Captação Epidemiológica do Instituto Nacional de Saúde Mental dos Estados Unidos (ECA-NIMH, a Pesquisa Nacional de Comorbidade (NCS, a Pesquisa de Morbidade Psiquiátrica na Grã-Bretanha (OPCS, o Estudo Brasileiro Multicêntrico de Morbidade Psiquiátrica e os estudos longitudinais conduzidos por Angst, em Zurique. As estimativas de prevalências de transtorno bipolar são relativamente baixas, independentemente do lugar onde a pesquisa foi conduzida, do tipo de instrumento diagnóstico usado e dos períodos de tempo para os quais a prevalência se aplica. A partir da introdução do conceito de espectro bipolar, ampliando as fronteiras diagnósticas do TB, as estimativas de prevalências encontradas são substancialmente mais altas. Tais estimativas, entretanto, ainda carecem de validação em estudos populacionais. O transtorno afetivo bipolar é igualmente prevalente entre homens e mulheres, sendo mais freqüente entre solteiros ou separados. Indivíduos acometidos têm maiores taxas de desemprego e estão mais sujeitos a utilizarem serviços médicos e serem hospitalizados. O custo e a eficácia dos tratamentos do TB devem ser balanceados com o alto custo individual e social associados à enfermidade.Information about the epidemiology of bipolar disorders is essential for providing a framework for the formulation of effective mental health policy. In the last two decades, population

  18. Silicon Germanium Heterojunction Bipolar Transistor for Digital Application

    Directory of Open Access Journals (Sweden)

    Engelin Shintadewi Julian

    2012-09-01

    Full Text Available Bipolar transistor performances can be characterized by figures of merit such as cutoff frequency, maximum frequency of oscillation and ECL gate delay. We studied the required figures of merit for digital application and the effects of lateral and vertical scaling to the figures of merit of SiGe HBT. With lateral scaling, the width of emitter finger is scaled down from 0.25 to 0.12 ?m while with the vertical scaling, the base width is scaled down to reduce the base delay. We also observed the effects of Ge profile and Ge fraction to the devices performances. Bipole3 5.3.1G is used to help us in the study. We found that high frequency cutoff and maximum frequency of oscillation as well as low ECL gate delay are all important for digital applications. Scaling down the emitter finger width enhanced the maximum frequency of oscillation and reduced ECL gate delay significantly while scaling down the base width increased the cutoff frequency and current gain.

  19. Si/Ge intermixing during Ge Stranski–Krastanov growth

    Directory of Open Access Journals (Sweden)

    Alain Portavoce

    2014-12-01

    Full Text Available The Stranski–Krastanov growth of Ge islands on Si(001 has been widely studied. The morphology changes of Ge islands during growth, from nucleation to hut/island formation and growth, followed by hut-to-dome island transformation and dislocation nucleation of domes, have been well described, even at the atomic scale, using techniques such as scanning tunneling microscopy and transmission electron microscopy. Although it is known that these islands do not consist of pure Ge (due to Si/Ge intermixing, the composition of the Ge islands is not precisely known. In the present work, atom probe tomography was used to study the composition of buried dome islands at the atomic scale, in the three-dimensional space. The core of the island was shown to contain about 55 atom % Ge, while the Ge composition surrounding this core decreases rapidly in all directions in the islands to reach a Ge concentration of about 15 atom %. The Ge distribution in the islands follows a cylindrical symmetry and Ge segregation is observed only in the {113} facets of the islands. The Ge composition of the wetting layer is not homogeneous, varying from 5 to 30 atom %.

  20. Annealing temperature effect on structure and electrical properties of films formed of Ge nanoparticles in SiO2

    International Nuclear Information System (INIS)

    Stavarache, Ionel; Lepadatu, Ana-Maria; Stoica, Toma; Ciurea, Magdalena Lidia

    2013-01-01

    Ge–SiO 2 films with high Ge/Si atomic ratio of about 1.86 were obtained by co-sputtering of Ge and SiO 2 targets and subsequently annealed at different temperatures between 600 and 1000 °C in a conventional furnace in order to show how the annealing process influences the film morphology concerning the Ge nanocrystal and/or amorphous nanoparticle formation and to study their electrical behaviour. Atomic force microscopy (AFM) imaging, Raman spectroscopy and electrical conductance measurements were performed in order to find out the annealing effect on the film surface morphology, as well as the Ge nanoparticle formation in correlation with the hopping conductivity of the films. AFM images show that the films annealed at 600 and 700 °C present a granular surface with particle height of about 15 nm, while those annealed at higher temperatures have smoother surface. The Raman investigations evidence Ge nanocrystals (including small ones) coexisting with amorphous Ge in the films annealed at 600 °C and show that almost all Ge is crystallized in the films annealed at 700 °C. The annealing at 800 °C disadvantages the Ge nanocrystal formation due to the strong Ge diffusion. This transition in Ge nanocrystals formation process by annealing temperature increase from 700 to 800 °C revealed by AFM and Raman spectroscopy measurements corresponds to a change in the electrical transport mechanism. Thus, in the 700 °C annealed films, the current depends on temperature according to a T −1/2 law which is typical for a tunnelling mechanism between neighbour Ge nanocrystals. In the 800 °C annealed films, the current–temperature characteristic has a T −1/4 dependence showing a hopping mechanism within an electronic band of localized states related to diffused Ge in SiO 2 .

  1. Mixed features in bipolar disorder.

    Science.gov (United States)

    Solé, Eva; Garriga, Marina; Valentí, Marc; Vieta, Eduard

    2017-04-01

    Mixed affective states, defined as the coexistence of depressive and manic symptoms, are complex presentations of manic-depressive illness that represent a challenge for clinicians at the levels of diagnosis, classification, and pharmacological treatment. The evidence shows that patients with bipolar disorder who have manic/hypomanic or depressive episodes with mixed features tend to have a more severe form of bipolar disorder along with a worse course of illness and higher rates of comorbid conditions than those with non-mixed presentations. In the updated Diagnostic and Statistical Manual of Mental Disorders (5th ed.; DSM-5), the definition of "mixed episode" has been removed, and subthreshold nonoverlapping symptoms of the opposite pole are captured using a "with mixed features" specifier applied to manic, hypomanic, and major depressive episodes. However, the list of symptoms proposed in the DSM-5 specifier has been widely criticized, because it includes typical manic symptoms (such as elevated mood and grandiosity) that are rare among patients with mixed depression, while excluding symptoms (such as irritability, psychomotor agitation, and distractibility) that are frequently reported in these patients. With the new classification, mixed depressive episodes are three times more common in bipolar II compared with unipolar depression, which partly contributes to the increased risk of suicide observed in bipolar depression compared to unipolar depression. Therefore, a specific diagnostic category would imply an increased diagnostic sensitivity, would help to foster early identification of symptoms and ensure specific treatment, as well as play a role in suicide prevention in this population.

  2. Single-crystalline Ni2Ge/Ge/Ni2Ge nanowire heterostructure transistors.

    Science.gov (United States)

    Tang, Jianshi; Wang, Chiu-Yen; Xiu, Faxian; Hong, Augustin J; Chen, Shengyu; Wang, Minsheng; Zeng, Caifu; Yang, Hong-Jie; Tuan, Hsing-Yu; Tsai, Cho-Jen; Chen, Lih Juann; Wang, Kang L

    2010-12-17

    In this study, we report on the formation of a single-crystalline Ni(2)Ge/Ge/Ni(2)Ge nanowire heterostructure and its field effect characteristics by controlled reaction between a supercritical fluid-liquid-solid (SFLS) synthesized Ge nanowire and Ni metal contacts. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) studies reveal a wide temperature range to convert the Ge nanowire to single-crystalline Ni(2)Ge by a thermal diffusion process. The maximum current density of the fully germanide Ni(2)Ge nanowires exceeds 3.5 × 10(7) A cm(-2), and the resistivity is about 88 μΩ cm. The in situ reaction examined by TEM shows atomically sharp interfaces for the Ni(2)Ge/Ge/Ni(2)Ge heterostructure. The interface epitaxial relationships are determined to be [Formula: see text] and [Formula: see text]. Back-gate field effect transistors (FETs) were also fabricated using this low resistivity Ni(2)Ge as source/drain contacts. Electrical measurements show a good p-type FET behavior with an on/off ratio over 10(3) and a one order of magnitude improvement in hole mobility from that of SFLS-synthesized Ge nanowire.

  3. Integrated Neurobiology of Bipolar Disorder

    Science.gov (United States)

    Maletic, Vladimir; Raison, Charles

    2014-01-01

    From a neurobiological perspective there is no such thing as bipolar disorder. Rather, it is almost certainly the case that many somewhat similar, but subtly different, pathological conditions produce a disease state that we currently diagnose as bipolarity. This heterogeneity – reflected in the lack of synergy between our current diagnostic schema and our rapidly advancing scientific understanding of the condition – limits attempts to articulate an integrated perspective on bipolar disorder. However, despite these challenges, scientific findings in recent years are beginning to offer a provisional “unified field theory” of the disease. This theory sees bipolar disorder as a suite of related neurodevelopmental conditions with interconnected functional abnormalities that often appear early in life and worsen over time. In addition to accelerated loss of volume in brain areas known to be essential for mood regulation and cognitive function, consistent findings have emerged at a cellular level, providing evidence that bipolar disorder is reliably associated with dysregulation of glial–neuronal interactions. Among these glial elements are microglia – the brain’s primary immune elements, which appear to be overactive in the context of bipolarity. Multiple studies now indicate that inflammation is also increased in the periphery of the body in both the depressive and manic phases of the illness, with at least some return to normality in the euthymic state. These findings are consistent with changes in the hypothalamic–pituitary–adrenal axis, which are known to drive inflammatory activation. In summary, the very fact that no single gene, pathway, or brain abnormality is likely to ever account for the condition is itself an extremely important first step in better articulating an integrated perspective on both its ontological status and pathogenesis. Whether this perspective will translate into the discovery of innumerable more homogeneous forms of

  4. Forbidden energy band gap in diluted a-Ge1−xSix:N films

    International Nuclear Information System (INIS)

    Guarneros, C.; Rebollo-Plata, B.; Lozada-Morales, R.; Espinosa-Rosales, J.E.; Portillo-Moreno, J.; Zelaya-Angel, O.

    2012-01-01

    By means of electron gun evaporation Ge 1−x Si x :N thin films, in the entire range 0 ≤ x ≤ 1, were prepared on Si (100) and glass substrates. The initial vacuum reached was 6.6 × 10 −4 Pa, then a pressure of 2.7 × 10 −2 Pa of high purity N 2 was introduced into the chamber. The deposition time was 4 min. Crucible-substrate distance was 18 cm. X-ray diffraction patterns indicate that all the films were amorphous (a-Ge 1−x Si x :N). The nitrogen concentration was of the order of 1 at% for all the films. From optical absorption spectra data and by using the Tauc method the energy band gap (E g ) was calculated. The Raman spectra only reveal the presence of Si-Si, Ge-Ge, and Si-Ge bonds. Nevertheless, infrared spectra demonstrate the existence of Si-N and Ge-N bonds. The forbidden energy band gap (E g ) as a function of x in the entire range 0 ≤ x ≤ 1 shows two well defined regions: 0 ≤ x ≤ 0.67 and 0.67 ≤ x ≤ 1, due to two different behaviors of the band gap, where for x > 0.67 exists an abruptly change of E g (x). In this case E g (x) versus x is different to the variation of E g in a-Ge 1−x Si x and a-Ge 1−x Si x :H. This fact can be related to the formation of Ge 3 N 4 and GeSi 2 N 4 when x ≤ 0.67, and to the formation of Si 3 N 4 and GeSi 2 N 4 for 0.67 ≤ x. - Highlights: ► Nitrogen doped amorphous Ge 1-x Si x thin films are grown by electron gun technique. ► Nitrogen atoms on E g of the a-Ge 1-x Si x films in the 0 £ x £ 1 range are analyzed. ► Variation in 0 £ x £ 1 range shows a warped change of E g in 1.0 – 3.6 eV range. ► The change in E g (x) behavior when x ∼ 0.67 was associated with Ge 2 SiN 4 presence.

  5. Microstructure and magnetic behavior of Mn doped GeTe chalcogenide semiconductors based phase change materials

    Science.gov (United States)

    Adam, Adam Abdalla Elbashir; Cheng, Xiaomin; Abuelhassan, Hassan H.; Miao, Xiang Shui

    2017-06-01

    Phase-change materials (PCMs) are the most promising candidates to be used as an active media in the universal data storage and spintronic devices, due to their large differences in physical properties of the amorphous-crystalline phase transition behavior. In the present study, the microstructure, magnetic and electrical behaviors of Ge0.94Mn0.06Te thin film were investigated. The crystallographic structure of Ge0.94Mn0.06Te thin film was studied sing X-ray diffractometer (XRD) and High Resolution Transmission Electron Microscope (HR-TEM). The XRD pattern showed that the crystallization structure of the film was rhombohedral phase for GeTe with a preference (202) orientation. The HR-TEM image of the crystalline Ge0.94Mn0.06Te thin film demonstrated that, there were two large crystallites and small amorphous areas. The magnetization as a function of the magnetic field analyses of both amorphous and crystalline states showed the ferromagnetic hysteretic behaviors. Then, the hole carriers concentration of the film was measured and it found to be greater than 1021 cm-3 at room temperature. Moreover, the anomalous of Hall Effect (AHE) was clearly observed for the measuring temperatures 5, 10 and 50 K. The results demonstrated that the magnitude of AHE decreased when the temperature was increasing.

  6. Tunneling, Current Gain, and Transconductance in Silicon-Germanium Heterojunction Bipolar Transistors Operating at Millikelvin Temperatures

    Science.gov (United States)

    Davidović, D.; Ying, H.; Dark, J.; Wier, B. R.; Ge, L.; Lourenco, N. E.; Omprakash, A. P.; Mourigal, M.; Cressler, J. D.

    2017-08-01

    Quantum-transport measurements in advanced silicon-germanium heterojunction bipolar transistors (SiGe HBTs) are presented and analyzed, including tunneling spectroscopy of discrete impurity levels localized within the transistor and the dependence on an applied magnetic field. The collector current at millikelvin temperatures is well accounted for by ideal electron tunneling throughout the entire base. The amplification principle at millikelvin temperatures is fundamentally quantum mechanical in nature: an increase in base voltage, requiring a moderate base current, creates an equal and opposite decrease in the tunneling barrier seen by the electrons in the emitter, thereby increasing the collector current significantly more than the base current, producing current gain. Highly scaled SiGe HBTs operate predictably at millikelvin temperatures, thus opening the possibility of viable SiGe millikelvin circuitry.

  7. Bipolar resistive switching in room temperature grown disordered vanadium oxide thin-film devices

    Science.gov (United States)

    Wong, Franklin J.; Sriram, Tirunelveli S.; Smith, Brian R.; Ramanathan, Shriram

    2013-09-01

    We demonstrate bipolar switching with high OFF/ON resistance ratios (>104) in Pt/vanadium oxide/Cu structures deposited entirely at room temperature. The SET (RESET) process occurs when negative (positive) bias is applied to the top Cu electrode. The vanadium oxide (VOx) films are amorphous and close to the vanadium pentoxide stoichiometry. We also investigated Cu/VOx/W structures, reversing the position of the Cu electrode, and found the same polarity dependence with respect to the top and bottom electrodes, which suggests that the bipolar nature is linked to the VOx layer itself. Bipolar switching can be observed at 100 °C, indicating that it not due to a temperature-induced metal-insulator transition of a vanadium dioxide second phase. We discuss how ionic drift can lead to the bipolar electrical behavior of our junctions, similar to those observed in devices based on several other defective oxides. Such low-temperature processed oxide switches could be of relevance to back-end or package integration processing schemes.

  8. Amorphous metal based nanoelectromechanical switch

    KAUST Repository

    Mayet, Abdulilah M.

    2013-04-01

    Nanoelectromechanical (NEM) switch is an interesting ultra-low power option which can operate in the harsh environment and can be a complementary element in complex digital circuitry. Although significant advancement is happening in this field, report on ultra-low voltage (pull-in) switch which offers high switching speed and area efficiency is yet to be made. One key challenge to achieve such characteristics is to fabricate nano-scale switches with amorphous metal so the shape and dimensional integrity are maintained to achieve the desired performance. Therefore, we report a tungsten alloy based amorphous metal with fabrication process development of laterally actuated dual gated NEM switches with 100 nm width and 200 nm air-gap to result in <5 volts of actuation voltage (Vpull-in). © 2013 IEEE.

  9. Investigation of inter-diffusion in bilayer GeTe/SnSe phase change memory films

    International Nuclear Information System (INIS)

    Devasia, Archana; MacMahon, David; Raoux, Simone; Campbell, Kristy A.; Kurinec, Santosh K.

    2012-01-01

    A metal-chalcogenide layer, SnSe, is inserted between the memory layer GeTe and the top electrode to form a phase change memory cell. The GeTe layer exhibits ovonic threshold switching at a threshold field of ∼ 110 V/μm. For subsequent implementation into applications and reliability, material inter-diffusion and sublimation are examined in bilayer phase change films of GeTe/SnSe. Transmission electron microscopy and parallel electron energy loss spectroscopy analyses reveal Sn migration to the GeTe layer, which is responsible for lowering the rhombohedral to cubic structural transformation temperature in GeTe. Incongruent sublimation of SnSe and GeTe is observed at temperatures higher than 500 °C. Severe volatilization of Se results in the separation of a metallic Sn phase. The use of Al 2 O 3 as a capping layer has been found to mitigate these effects. - Highlights: ► In the as-deposited state, GeTe is amorphous and SnSe is orthorhombic in structure. ► After 300 °C, Sn migration results in the formation of a Ge x Sn 1−x Te solid solution. ► Film decomposition and incongruent sublimation are observed at high temperatures. ► A consequence of incongruent sublimation is the separation of metallic Sn phase. ► Al2O3 capping mitigates volatilization and Sn phase separation at high temperatures.

  10. Transient photoconductivity in amorphous semiconductors

    International Nuclear Information System (INIS)

    Mpawenayo, P.

    1997-07-01

    Localized states in amorphous semiconductors are divided in disorder induced shallow trap levels and dangling bonds deep states. Dangling bonds are assumed here to be either neutral or charged and their energy distribution is a single gaussian. Here, it is shown analytically that transient photocurrent in amorphous semiconductors is fully controlled by charge carriers transitions between localized states for one part and tunneling hopping carriers on the other. Localized dangling bonds deep states act as non radiative recombination centres, while hopping tunnelling is assisted by the Coulomb interaction between defects sites. The half-width of defects distribution is the disorder parameter that determines the carrier hopping time between defects sites. The macroscopic time that explains the long decay response times observed will all types of amorphous semiconductors is duly thought to be temperature dependent. Basic equations developed by Longeaud and Kleider are solved for the general case of a semiconductor after photo-generation. It turns out that the transient photoconductivity decay has two components; one with short response times from carriers trap-release transitions between shallow levels and extended states and a hopping component made of inter-dependent exponentials whose time constants span in larger ranges depending on disorder. The photoconductivity hopping component appears as an additional term to be added to photocurrents derived from existing models. The results of the present study explain and complete the power law decay derived in the multiple trapping models developed 20 years ago only in the approximation of the short response time regime. The long response time regime is described by the hopping macroscopic time. The present model is verified for all samples of amorphous semiconductors known so far. Finally, it is proposed to improved the modulated photoconductivity calculation techniques by including the long-lasting hopping dark documents

  11. Uranium incorporation into amorphous silica.

    Science.gov (United States)

    Massey, Michael S; Lezama-Pacheco, Juan S; Nelson, Joey M; Fendorf, Scott; Maher, Kate

    2014-01-01

    High concentrations of uranium are commonly observed in naturally occurring amorphous silica (including opal) deposits, suggesting that incorporation of U into amorphous silica may represent a natural attenuation mechanism and promising strategy for U remediation. However, the stability of uranium in opaline silicates, determined in part by the binding mechanism for U, is an important factor in its long-term fate. U may bind directly to the opaline silicate matrix, or to materials such as iron (hydr)oxides that are subsequently occluded within the opal. Here, we examine the coordination environment of U within opaline silica to elucidate incorporation mechanisms. Precipitates (with and without ferrihydrite inclusions) were synthesized from U-bearing sodium metasilicate solutions, buffered at pH ∼ 5.6. Natural and synthetic solids were analyzed with X-ray absorption spectroscopy and a suite of other techniques. In synthetic amorphous silica, U was coordinated by silicate in a double corner-sharing coordination geometry (Si at ∼ 3.8-3.9 Å) and a small amount of uranyl and silicate in a bidentate, mononuclear (edge-sharing) coordination (Si at ∼ 3.1-3.2 Å, U at ∼ 3.8-3.9 Å). In iron-bearing synthetic solids, U was adsorbed to iron (hydr)oxide, but the coordination environment also contained silicate in both edge-sharing and corner-sharing coordination. Uranium local coordination in synthetic solids is similar to that of natural U-bearing opals that retain U for millions of years. The stability and extent of U incorporation into opaline and amorphous silica represents a long-term repository for U that may provide an alternative strategy for remediation of U contamination.

  12. Ga–Ge–Te amorphous thin films fabricated by pulsed laser deposition

    Energy Technology Data Exchange (ETDEWEB)

    Němec, P. [Department of Graphic Arts and Photophysics, Faculty of Chemical Technology, University of Pardubice, Studentská 573, 53210 Pardubice (Czech Republic); Nazabal, V., E-mail: virginie.nazabal@univ-rennes1.fr [Department of Graphic Arts and Photophysics, Faculty of Chemical Technology, University of Pardubice, Studentská 573, 53210 Pardubice (Czech Republic); Equipe Verres et Céramiques, UMR-CNRS 6226, Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes 1, 35042 Rennes Cedex (France); Dussauze, M. [ISM, UMR-CNRS 5255, Université de Bordeaux, 33400 Talence (France); Ma, H.-L.; Bouyrie, Y.; Zhang, X.-H. [Equipe Verres et Céramiques, UMR-CNRS 6226, Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes 1, 35042 Rennes Cedex (France)

    2013-03-01

    UV pulsed laser deposition was employed for the fabrication of amorphous Ga–Ge–Te thin films. The local structure of the bulk glasses as well as corresponding thin films was studied using Raman scattering spectroscopy; the main structural motifs were found to be [GeTe{sub 4}], eventually [GaTe{sub 4}] corner-sharing tetrahedra and disordered Te chains. Optical functions of the films (refractive index, extinction coefficient) were characterized by variable angle spectroscopic ellipsometry. Photostability experiments showed all Ga–Ge–Te laser deposited films to be stable against 1550 nm laser irradiation in an as-deposited state. In an annealed state, the most photostable composition seems to be Ga{sub 10}Ge{sub 15}Te{sub 75}. This particular composition was further studied from the point of view of thermal stability and stability against ageing in as-deposited state. - Highlights: ► Pulsed laser deposition was used for fabrication of amorphous Ga–Ge–Te thin films. ► GeTe{sub 4}, eventually GaTe{sub 4} tetrahedra and disordered Te chains form the film structure. ► Optical functions of Ge–Ga–Te films were characterized by spectroscopic ellipsometry. ► All as-deposited Ga–Ge–Te thin films are stable against 1550 nm irradiation. ► In annealed state, the most photostable composition seems to be Ga{sub 10}Ge{sub 15}Te{sub 75}.

  13. Role of Activation Energy in Resistance Drift of Amorphous Phase Change Materials

    Science.gov (United States)

    Wimmer, Martin; Kaes, Matthias; Dellen, Christian; Salinga, Martin

    2014-12-01

    The time evolution of the resistance of amorphous thin films of the phase change materials Ge2Sb2Te5, GeTe and AgIn-Sb2Te is measured during annealing at T=80°C. The annealing process is interrupted by several fast temperature dips to determine the changing temperature dependence of the resistance. This procedure enables us to identify to what extent the resistance increase over time can be traced back to an increase in activation energy EA or to a rise of the prefactor R*. We observe that, depending on the material, the dominating contribution to the increase in resistance during annealing can be either a change in activation energy (Ge2Sb2Te5) or a change in prefactor (AgIn-Sb2Te). In the case of GeTe, both contribute about equally. We conclude that any phenomenological model for the resistance drift in amorphous phase change materials that is based on the increase of one parameter alone (e.g. the activation energy) cannot claim general validity.

  14. Fabrication of Hydrogenated Amorphous Germanium Thin Layer Film and ItsCharacterization

    International Nuclear Information System (INIS)

    Agus-Santoso; Lely-Susita RM; Tjipto-Sujitno

    2000-01-01

    Fabrication of hydrogenated amorphous Germanium thin film by vacuumevaporation method and then deposition with hydrogen atom by glow dischargeplasma radio frequency has been done. This germanium amorphous (a-Ge) thinfilm involves a lot of dangling bonds in the network due to the irregularityof the atomic structures and it will decrease is conductivity. To improve theband properties of (a-Ge) thin film layer a hydrogenated plasma isintroduced. Process of introducing of the hydrogen into the a-Ge film is meanto reduce the dangling bonds so that the best electric conductivity of a Ge:Hthin film will obtained. To identify the hydrogen atom in the sample acharacterization using infrared spectrometer has been done, as well as themeasurement of conductivity of the samples. From the characterization usinginfrared spectroscopy the existence of hydrogen atom was found at absorptionpeak with wave number 1637.5 cm -1 , while the optimum conductivity of thesample 1634.86 Ω -1 cm -1 was achieved at 343 o K. (author)

  15. Amorphous Semiconductors: From Photocatalyst to Computer Memory

    Science.gov (United States)

    Sundararajan, Mayur

    encouraging but inconclusive. Then the method was successfully demonstrated on mesoporous TiO2SiO 2 by showing a shift in its optical bandgap. One of the special class of amorphous semiconductors is chalcogenide glasses, which exhibit high ionic conductivity even at room temperature. When metal doped chalcogenide glasses are under an electric field, they become electronically conductive. These properties are exploited in the computer memory storage application of Conductive Bridging Random Access Memory (CBRAM). CBRAM is a non-volatile memory that is a strong contender to replace conventional volatile RAMs such as DRAM, SRAM, etc. This technology has already been commercialized, but the working mechanism is still not clearly understood especially the nature of the conductive bridge filament. In this project, the CBRAM memory cells are fabricated by thermal evaporation method with Agx(GeSe 2)1-x as the solid electrolyte layer, Ag as the active electrode and Au as the inert electrode. By careful use of cyclic voltammetry, the conductive filaments were grown on the surface and the bulk of the solid electrolyte. The comparison between the two filaments revealed major differences leading to contradiction with the existing working mechanism. After compiling all the results, a modified working mechanism is proposed. SAXS is a powerful tool to characterize nanostructure of glasses. The analysis of the SAXS data to get useful information are usually performed by different programs. In this project, Irena and GIFT programs were compared by performing the analysis of the SAXS data of glass and glass ceramics samples. Irena was shown to be not suitable for the analysis of SAXS data that has a significant contribution from interparticle interactions. GIFT was demonstrated to be better suited for such analysis. Additionally, the results obtained by programs for samples with low interparticle interactions were shown to be consistent.

  16. Thermal annealing studies of GeTe-Sb2Te3 alloys with multiple interfaces

    Directory of Open Access Journals (Sweden)

    Valeria Bragaglia

    2017-08-01

    Full Text Available A high degree of vacancy ordering is obtained by annealing amorphous GeTe-Sb2Te3 (GST alloys deposited on a crystalline substrate, which acts as a template for the crystallization. Under annealing the material evolves from amorphous to disordered rocksalt, to ordered rocksalt with vacancies arranged into (111 oriented layers, and finally converts into the stable trigonal phase. The role of the interface in respect to the formation of an ordered crystalline phase is studied by comparing the transformation stages of crystalline GST with and without a capping layer. The capping layer offers another crystallization interface, which harms the overall crystalline quality.

  17. Role of the nano amorphous interface in the crystallization of Sb2Te3 towards non-volatile phase change memory: insights from first principles.

    Science.gov (United States)

    Wang, Xue-Peng; Chen, Nian-Ke; Li, Xian-Bin; Cheng, Yan; Liu, X Q; Xia, Meng-Jiao; Song, Z T; Han, X D; Zhang, S B; Sun, Hong-Bo

    2014-06-14

    The nano amorphous interface is important as it controls the phase transition for data storage. Yet, atomic scale insights into such kinds of systems are still rare. By first-principles calculations, we obtain the atomic interface between amorphous Si and amorphous Sb2Te3, which prevails in the series of Si-Sb-Te phase change materials. This interface model reproduces the experiment-consistent phenomena, i.e. the amorphous stability of Sb2Te3, which defines the data retention in phase change memory, and is greatly enhanced by the nano interface. More importantly, this method offers a direct platform to explore the intrinsic mechanism to understand the material function: (1) by steric effects through the atomic "channel" of the amorphous interface, the arrangement of the Te network is significantly distorted and is separated from the p-orbital bond angle in the conventional phase-change material; and (2) through the electronic "channel" of the amorphous interface, high localized electrons in the form of a lone pair are "projected" to Sb2Te3 from amorphous Si by a proximity effect. These factors set an effective barrier for crystallization and improve the amorphous stability, and thus data retention. The present research and scheme sheds new light on the engineering and manipulation of other key amorphous interfaces, such as Si3N4/Ge2Sb2Te5 and C/Sb2Te3, through first-principles calculations towards non-volatile phase change memory.

  18. Improvement of memory window and retention with low trap density in hydrogenated-amorphous-silicon-germanium nonvolatile memory

    International Nuclear Information System (INIS)

    Choi, Woojin; Jang, Kyungsoo; Raja, Jayapal; Cho, Jaehyun; Nguyen, Hong Hanh; Kim, Jiwoong; Lee, YounJung; Nagarajan, Balaji; Yi, Junsin; Kim, Minbum

    2013-01-01

    We report the SiO 2 /SiO X /SiO X N Y (OO X O N ) stacked nonvolatile memory (NVM) using hydrogenated amorphous silicon germanium (a-Si X Ge 1–X :H) as an active channel layer. In NVMs, the reduction of interface trap density is one of the key issues to improve device performance including memory window and retention. The NVMs using a-SiGe:H as the active channel overcame the limitation of small memory window size and poor retention characteristics by controlling the interface trap density using different Ge contents in the surface SiGe layer. For a-Si:H NVM that does not contain Ge, the memory size is about 5.15 V, which is quite large, with a programming voltage of −7 V and an erasing voltage of +15 V. However, the retention time of over 10 years is almost impossible. For a-SiGe:H NVM with 20% Ge, the memory size is as large as 7.38 V and the retention data of ∼58% is possible even after 10 years due to the reduced trap density in OO X O N and channel layers. When the Ge content is more than 20%, the memory size and retention property after 10 years decrease rapidly. When the contents of Ge in SiGe films reach a certain point, they act as defects lowering the properties. The results of NVM devices using a-SiGe:H (Ge 20%) as an active channel layer demonstrate that they have switching characteristics suitable for data storage such as a threshold voltage window. (paper)

  19. On the crystallization of thin films composed of Sb3.6Te with Ge for rewritable data storage

    NARCIS (Netherlands)

    Kooi, BJ; De Hosson, JTM

    2004-01-01

    This article addresses the crystallization of amorphous Sb3.6Te films (40 nm thick) and 5 at. % Ge containing Sb3.6Te films (10, 20, and 40 nm thick) as studied with transmission electron microcopy using in situ annealing. These materials exhibit growth-dominated crystallization, in contrast to the

  20. In-situ TEM study of the crystallization of thin films composed of Sb3.6Te with Ge

    NARCIS (Netherlands)

    Kooi, BJ; Groot, WMG; De Hosson, JTM; Ahner, JW; Levy, J; Hesselink, L; Mijiritskii, A

    2004-01-01

    This paper addresses the crystallization of amorphous Sb3.6Te films (40 nm thick) and 5 at.% Ge containing Sb3.6Te films (10, 20 and 40 nm thick) as studied using in-situ annealing in a Transmission Electron Microscope (TEM). These materials show growth-dominated crystallization, in contrast to

  1. Bipolar polygenic loading and bipolar spectrum features in major depressive disorder

    NARCIS (Netherlands)

    Wiste, Anna; Robinson, Elise B.; Milaneschi, Yuri; Meier, Sandra; Ripke, Stephan; Clements, Caitlin C.; Fitzmaurice, Garrett M.; Rietschel, Marcella; Penninx, Brenda W.; Smoller, Jordan W.; Perlis, Roy H.

    Objectives Family and genetic studies indicate overlapping liability for major depressive disorder and bipolar disorder. The purpose of the present study was to determine whether this shared genetic liability influences clinical presentation. Methods A polygenic risk score for bipolar disorder,

  2. Rapid Thermal annealing of silicon layers amorphized by ion implantation

    International Nuclear Information System (INIS)

    Hasenack, C.M.

    1986-01-01

    The recrystallization behavior and the supression mechanisms of the residual defects of silicon layers amorphized by ion implantation, were investigated. The samples were annealed with the aid of a rapid thermal annealing (RTA) system at temperature range from 850 to 1200 0 C, and annealing time up to 120 s. Random and aligned Rutherford backscattering spectroscopy were used to analyse the samples. Similarities in the recrystallization behavior for layers implanted with ions of the same chemical groups such as As or Sb; Ge, Sn or Pb, In or Ga, are observed. The results show that the effective supression of resisual defects of the recrystallired layers is vinculated to the redistribution of impurities via thermal diffusion. (author) [pt

  3. Colloidal Photoluminescent Amorphous Porous Silicon, Methods Of Making Colloidal Photoluminescent Amorphous Porous Silicon, And Methods Of Using Colloidal Photoluminescent Amorphous Porous Silicon

    KAUST Repository

    Chaieb, Sahraoui

    2015-04-09

    Embodiments of the present disclosure provide for a colloidal photoluminescent amorphous porous silicon particle suspension, methods of making a colloidal photoluminescent amorphous porous silicon particle suspension, methods of using a colloidal photoluminescent amorphous porous silicon particle suspension, and the like.

  4. Unsplit bipolar pulse forming line

    Science.gov (United States)

    Rhodes, Mark A [Pleasanton, CA

    2011-05-24

    A bipolar pulse forming transmission line module and system for linear induction accelerators having first, second, third, and fourth planar conductors which form a sequentially arranged interleaved stack having opposing first and second ends, with dielectric layers between the conductors. The first and second planar conductors are connected to each other at the first end, and the first and fourth planar conductors are connected to each other at the second end via a shorting plate. The third planar conductor is electrically connectable to a high voltage source, and an internal switch functions to short at the first end a high voltage from the third planar conductor to the fourth planar conductor to produce a bipolar pulse at the acceleration axis with a zero net time integral. Improved access to the switch is enabled by an aperture through the shorting plate and the proximity of the aperture to the switch.

  5. Course of Subthreshold Bipolar Disorder in Youth: Diagnostic Progression from Bipolar Disorder Not Otherwise Specified

    Science.gov (United States)

    Axelson, David A.; Birmaher, Boris; Strober, Michael A.; Goldstein, Benjamin I.; Ha, Wonho; Gill, Mary Kay; Goldstein, Tina R.; Yen, Shirley; Hower, Heather; Hunt, Jeffrey I.; Liao, Fangzi; Iyengar, Satish; Dickstein, Daniel; Kim, Eunice; Ryan, Neal D.; Frankel, Erica; Keller, Martin B.

    2011-01-01

    Objective: To determine the rate of diagnostic conversion from an operationalized diagnosis of bipolar disorder not otherwise specified (BP-NOS) to bipolar I disorder (BP-I) or bipolar II disorder (BP-II) in youth over prospective follow-up and to identify factors associated with conversion. Method: Subjects were 140 children and adolescents…

  6. The role of the surfaces in the photon absorption in Ge nanoclusters embedded in silica

    Directory of Open Access Journals (Sweden)

    Nicotra Giuseppe

    2011-01-01

    Full Text Available Abstract The usage of semiconductor nanostructures is highly promising for boosting the energy conversion efficiency in photovoltaics technology, but still some of the underlying mechanisms are not well understood at the nanoscale length. Ge quantum dots (QDs should have a larger absorption and a more efficient quantum confinement effect than Si ones, thus they are good candidate for third-generation solar cells. In this work, Ge QDs embedded in silica matrix have been synthesized through magnetron sputtering deposition and annealing up to 800°C. The thermal evolution of the QD size (2 to 10 nm has been followed by transmission electron microscopy and X-ray diffraction techniques, evidencing an Ostwald ripening mechanism with a concomitant amorphous-crystalline transition. The optical absorption of Ge nanoclusters has been measured by spectrophotometry analyses, evidencing an optical bandgap of 1.6 eV, unexpectedly independent of the QDs size or of the solid phase (amorphous or crystalline. A simple modeling, based on the Tauc law, shows that the photon absorption has a much larger extent in smaller Ge QDs, being related to the surface extent rather than to the volume. These data are presented and discussed also considering the outcomes for application of Ge nanostructures in photovoltaics. PACS: 81.07.Ta; 78.67.Hc; 68.65.-k

  7. Bipolar (spectrum) disorder and mood stabilization: standing at the crossroads?

    OpenAIRE

    De Fruyt, Jurgen; Demyttenaere, Koen

    2007-01-01

    Diagnosis and treatment of bipolar disorder has long been a neglected discipline. Recent years have shown an upsurge in bipolar research. When compared to major depressive disorder, bipolar research still remains limited and more expert based than evidence based. In bipolar diagnosis the focus is shifting from classic mania to bipolar depression and hypomania. There is a search for bipolar signatures in symptoms and course of major depressive episodes. The criteria for hypomania are softened,...

  8. [Bipolar disorders in DSM-5].

    Science.gov (United States)

    Severus, E; Bauer, M

    2014-05-01

    In spring 2013 the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) edited by the American Psychiatric Association was published. The DSM-5 has also brought some important changes regarding bipolar disorders. The goal of this manuscript is to review the novelties in DSM-5 and to evaluate the implications of these changes. The diagnostic criteria as well as the additional remarks provided in the running text of DSM-5 were carefully appraised. For the first time diagnostic criteria are provided for disorders which up to now have been considered as subthreshold bipolar disorders. Furthermore, mixed episodes were eliminated and instead a mixed specifier was introduced. An increase in goal-directed activity/energy is now one of the obligatory symptoms for a (hypo)manic episode. Diagnostic guidance is provided as to when a (hypo)manic episode that has developed during treatment with an antidepressant has to be judged to be causally related to antidepressants and when this episode has only occurred coincidentally with antidepressant use. While some of the novelties are clearly useful, e.g. addition of increased goal-directed activity/energy as obligatory symptom for (hypo)manic episodes, this remains to be demonstrated for others, such as the definition of various subthreshold bipolar disorders.

  9. Hydrogen in disordered and amorphous solids

    International Nuclear Information System (INIS)

    Bambakidis, G; Bowman, R.C.

    1986-01-01

    This book presents information on the following topoics: elements of the theory of amorphous semiconductors; electronic structure of alpha-SiH; fluctuation induced gap states in amorphous hydrogenated silicon; hydrogen on semiconductor surfaces; the influence of hydrogen on the defects and instabilities in hydrogenated amorphous silicon; deuteron magnetic resonance in some amorphous semiconductors; formation of amorphous metals by solid state reactions of hydrogen with an intermetallic compound; NMR studies of the hydrides of disordered and amorphous alloys; neutron vibrational spectroscopy of disordered metal-hydrogen system; dynamical disorder of hydrogen in LaNi /SUB 5-y/ M /SUB y/ hydrides studied by quasi-elastic neutron scattering; recent studies of intermetallic hydrides; tritium in Pd and Pd /SUB 0.80/ Sg /SUB 0.20/ ; and determination of hydrogen concentration in thin films of absorbing materials

  10. Bipolar Disorder and Obsessive Compulsive Disorder Comorbidity

    Directory of Open Access Journals (Sweden)

    Necla Keskin

    2014-08-01

    Full Text Available The comorbidity of bipolar disorder and anxiety disorders is a well known concept. Obsessive-compulsive disorder is the most commonly seen comorbid anxiety disorder in bipolar patients. Some genetic variants, neurotransmitters especially serotonergic systems and second-messenger systems are thought to be responsible for its etiology. Bipolar disorder alters the clinical aspects of obsessive compulsive disorder and is associated with poorer outcome. The determination of comorbidity between bipolar disorder and obsessive compulsive disorder is quite important for appropriate clinical management and treatment. [Psikiyatride Guncel Yaklasimlar - Current Approaches in Psychiatry 2014; 6(4.000: 429-437

  11. a-SiGe:H alloy material limitations and device considerations

    International Nuclear Information System (INIS)

    Fortmann, C.M.

    1990-01-01

    The electron mobility of intrinsic amorphous SiGe films is found to depend on the hydrogen content. Deposition conditions that influence hydrogen content are discussed. The best C H a-SiGe:H alloys of 1.3 eV band gap are used in solar cells. Solar cell analysis is used to determine both hole and electron transport. The electron mobility is reduced by alloying; however, the hole transport of the alloy is not significantly different from that of device quality a-Si:H. Cell designs that minimize performance loss due to poor electron mobility are considered

  12. The physics and applications of amorphous semiconductors

    CERN Document Server

    Madan, Arun

    1988-01-01

    This comprehensive, detailed treatise on the physics and applications of the new emerging technology of amorphous semiconductors focuses on specific device research problems such as the optimization of device performance. The first part of the book presents hydrogenated amorphous silicon type alloys, whose applications include inexpensive solar cells, thin film transistors, image scanners, electrophotography, optical recording and gas sensors. The second part of the book discusses amorphous chalcogenides, whose applications include electrophotography, switching, and memory elements. This boo

  13. Polyamorphous transition in amorphous fullerites C70

    International Nuclear Information System (INIS)

    Borisova, P. A.; Agafonov, S. S.; Glazkov, V. P.; D’yakonova, N. P.; Somenkov, V. A.

    2011-01-01

    Samples of amorphous fullerites C 70 have been obtained by mechanical activation (grinding in a ball mill). The structure of the samples has been investigated by neutron and X-ray diffraction. The high-temperature (up to 1200°C) annealing of amorphous fullerites revealed a polyamorphous transition from molecular to atomic glass, which is accompanied by the disappearance of fullerene halos at small scattering angles. Possible structural versions of the high-temperature amorphous phase are discussed.

  14. Structure and electronic properties features of amorphous chalhogenide semiconductor films prepared by ion-plasma spraying

    Energy Technology Data Exchange (ETDEWEB)

    Korobova, N., E-mail: korobova3@mail.ru; Timoshenkov, S. [Department of Microelectronics, National Research University of Electronic Technology (MIET), Zelenograd (Russian Federation); Almasov, N.; Prikhodko, O. [al-Farabi Kazakh National University, Almaty (Kazakhstan); Tsendin, K. [Ioffe Physical-Technical Institute, Russian Academy of Sciences, St. Petersburg (Russian Federation)

    2014-10-21

    Structure of amorphous chalcogenide semiconductor glassy As-S-Se films, obtained by high-frequency (HF) ion-plasma sputtering has been investigated. It was shown that the length of the atomic structure medium order and local structure were different from the films obtained by thermal vacuum evaporation. Temperature dependence of dark conductivity, as well as the dependence of the spectral transmittance has been studied. Conductivity value was determined at room temperature. Energy activation conductivity and films optical band gap have been calculated. Temperature and field dependence of the drift mobility of charge carriers in the HF As-S-Se films have been shown. Bipolarity of charge carriers drift mobility has been confirmed. Absence of deep traps for electrons in the As{sub 40}Se{sub 30}S{sub 30} spectrum of localized states for films obtained by HF plasma ion sputtering was determined. Bipolar drift of charge carriers was found in amorphous As{sub 40}Se{sub 30}S{sub 30} films obtained by ion-plasma sputtering of high-frequency, unlike the films of these materials obtained by thermal evaporation.

  15. Simultaneous ultra-long data retention and low power based on Ge10Sb90/SiO2 multilayer thin films

    Science.gov (United States)

    You, Haipeng; Hu, Yifeng; Zhu, Xiaoqin; Zou, Hua; Song, Sannian; Song, Zhitang

    2018-02-01

    In this article, Ge10Sb90/SiO2 multilayer thin films were prepared to improve thermal stability and data retention for phase change memory. Compared with Ge10Sb90 monolayer thin film, Ge10Sb90 (1 nm)/SiO2 (9 nm) multilayer thin film had higher crystallization temperature and resistance contrast between amorphous and crystalline states. Annealed Ge10Sb90 (1 nm)/SiO2 (9 nm) had uniform grain with the size of 15.71 nm. After annealing, the root-mean-square surface roughness for Ge10Sb90 (1 nm)/SiO2 (9 nm) thin film increased slightly from 0.45 to 0.53 nm. The amorphization time for Ge10Sb90 (1 nm)/SiO2 (9 nm) thin film (2.29 ns) is shorter than Ge2Sb2Te5 (3.56 ns). The threshold voltage of a cell based on Ge10Sb90 (1 nm)/SiO2 (9 nm) (3.57 V) was smaller than GST (4.18 V). The results indicated that Ge10Sb90/SiO2 was a promising phase change thin film with high thermal ability and low power consumption for phase change memory application.

  16. Amorphous silicon based radiation detectors

    International Nuclear Information System (INIS)

    Perez-Mendez, V.; Cho, G.; Drewery, J.; Jing, T.; Kaplan, S.N.; Qureshi, S.; Wildermuth, D.; Fujieda, I.; Street, R.A.

    1991-07-01

    We describe the characteristics of thin(1 μm) and thick (>30μm) hydrogenated amorphous silicon p-i-n diodes which are optimized for detecting and recording the spatial distribution of charged particles, x-rays and γ rays. For x-ray, γ ray, and charged particle detection we can use thin p-i-n photosensitive diode arrays coupled to evaporated layers of suitable scintillators. For direct detection of charged particles with high resistance to radiation damage, we use the thick p-i-n diode arrays. 13 refs., 7 figs

  17. Ge and GeOx films as sacrificial layer for MEMS technology based on piezoelectric AlN: etching and planarization processes (Invited Paper)

    Science.gov (United States)

    Sangrador, J.; Olivares, J.; Iborra, E.; Vergara, L.; Clement, M.; Sanz-Hervas, A.

    2005-07-01

    In this article we present a study of deposition and etching techniques of germanium (Ge) and amorphous oxygen germanium (GeOx) films, with the aim of using them as sacrificial layer in the fabrication of AlN-based MEMS by surface micromachining processes. The Ge and GeOx layers were deposited by RF magnetron sputtering in Ar and Ar/O2 atmospheres. By controlling the process parameters we were able to set the final composition of the GeOx films, which was assessed by FTIR measurements. We have studied the etch rates of GeOx films with x ranging from 0 to 1 in H2O2 and H2O2/acid solutions. Depending on the etching temperature and the oxygen content in the layers, etch rates ranging from 0.2 to 2 μm/min were obtained. Nearly stoichiometric germanium oxide (GeO2) was etched in pure H2O at very high rate (>1 μm/min at room temperature). We have also developed a chemomechanical polishing (CMP) process for the planarization of Ge and GeOx. The influence of the slurries containing diverse powders (CeO2, Al2O3) and chemical agents (NH4OH, HCl), the different pads, and the various process parameters on the removal rate and the final sample topography has been studied. Finally, we have analysed the compatibility of the materials involved in the process flow with the processes of planarization and removal of the sacrificial layers.

  18. Structure of 78Ge from the 76Ge(t,p)78Ge reaction

    International Nuclear Information System (INIS)

    Ardouin, D.; Lebrun, C.; Guilbault, F.; Remaud, B.; Vergnes, M.N.; Rotbard, G.; Kumar, K.

    1978-01-01

    The 76 Ge(t,p) 78 Ge reaction has been performed at a bombarding energy of 17 MeV. Thirteen excited states below 3 MeV excitation are reported with Jsup(π) values obtained by comparison to DWBA analysis. A comparison to a dynamical deformation theory is made and the results suggest 78 Ge is a transitional nucleus nearing spherical shape due to the proximity of the N-50 closed shell

  19. Bipolar mixed features - Results from the comparative effectiveness for bipolar disorder (Bipolar CHOICE) study.

    Science.gov (United States)

    Tohen, Mauricio; Gold, Alexandra K; Sylvia, Louisa G; Montana, Rebecca E; McElroy, Susan L; Thase, Michael E; Rabideau, Dustin J; Nierenberg, Andrew A; Reilly-Harrington, Noreen A; Friedman, Edward S; Shelton, Richard C; Bowden, Charles L; Singh, Vivek; Deckersbach, Thilo; Ketter, Terence A; Calabrese, Joseph R; Bobo, William V; McInnis, Melvin G

    2017-08-01

    DSM-5 changed the criteria from DSM-IV for mixed features in mood disorder episodes to include non-overlapping symptoms of depression and hypomania/mania. It is unknown if, by changing these criteria, the same group would qualify for mixed features. We assessed how those meeting DSM-5 criteria for mixed features compare to those meeting DSM-IV criteria. We analyzed data from 482 adult bipolar patients in Bipolar CHOICE, a randomized comparative effectiveness trial. Bipolar diagnoses were confirmed through the MINI International Neuropsychiatric Interview (MINI). Presence and severity of mood symptoms were collected with the Bipolar Inventory of Symptoms Scale (BISS) and linked to DSM-5 and DSM-IV mixed features criteria. Baseline demographics and clinical variables were compared between mood episode groups using ANOVA for continuous variables and chi-square tests for categorical variables. At baseline, the frequency of DSM-IV mixed episodes diagnoses obtained with the MINI was 17% and with the BISS was 20%. Using DSM-5 criteria, 9% of participants met criteria for hypomania/mania with mixed features and 12% met criteria for a depressive episode with mixed features. Symptom severity was also associated with increased mixed features with a high rate of mixed features in patients with mania/hypomania (63.8%) relative to those with depression (8.0%). Data on mixed features were collected at baseline only and thus do not reflect potential patterns in mixed features within this sample across the study duration. The DSM-5 narrower, non-overlapping definition of mixed episodes resulted in fewer patients who met mixed criteria compared to DSM-IV. Copyright © 2017. Published by Elsevier B.V.

  20. [Thinking organization and defense mechanisms in bipolar disorders. Clinical and psychopathological study on bipolar I and bipolar II].

    Science.gov (United States)

    Lo Baido, Rosa; Di Blasi, Marie; Alfano, Pietro; Audino, Palma; Bellavia, Carmela; Blando, Anna Antonia; Merendino, Adelaide; Messina, Rossana; Poma, Maria Luisa; La Grutta, Sabina

    2013-01-01

    The aim of this research is to explore the psychical functioning in bipolar I or bipolar II disorder people through the analysis and comparison of their thought styles and defense patterns. 29 bipolar I and bipolar II people afferent to Palermo University Policlinical Psychriatic Hospital Department were selected during the whole 2009-2010 year. The following tests were administred: Wechsler Adult Intelligent Scale-R (WAIS-R) in order to measure the general cognitive function; Defense Mechanisms Inventory (DMI) in order to measure defense patterns. Afterwards, the results of the two tests were analysed and compared. Bipolar disorder people use cognitive mechanisms and defense strategies that are very different from standard population. Bipolar I subjects show both wider and more serious cognitive deterioration and stricter defense mechanisms than bipolar II subjects. Generally bipolar patients show an immature personality based on archaic mechanisms that can be found in all the spheres of their personality: emotions, cognition, Ego-strength, adaptability to reality. The peculiar achieved cognitive and defense profile leads to important considerations about how psychological strategies can contribute to use "bespoke" treatments for these patients.

  1. 75 FR 47318 - GE Asset Management Incorporated and GE Investment Distributors, Inc.; Notice of Application and...

    Science.gov (United States)

    2010-08-05

    ...] GE Asset Management Incorporated and GE Investment Distributors, Inc.; Notice of Application and.... Applicants: GE Asset Management Incorporated (``GEAM'') and GE Investment Distributors, Inc. (``GEID... of Investment Management, Office of Investment Company Regulation). SUPPLEMENTARY INFORMATION: The...

  2. Scanning transmission electron microscopy analysis of Ge(O)/(graphitic carbon nitride) nanocomposite powder

    Energy Technology Data Exchange (ETDEWEB)

    Kawasaki, Masahiro [JEOL USA Inc., 11 Dearborn Road, Peabody, MA 01960 (United States); Sompetch, Kanganit [Department of Chemistry and Materials Science Research Center, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Sarakonsri, Thapanee, E-mail: tsarakonsri@gmail.com [Department of Chemistry and Materials Science Research Center, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Shiojiri, Makoto [Kyoto Institute of Technology, Kyoto 606-8585 (Japan); School of Science and Engineering, University of Toyama, Toyama 930-8555 (Japan)

    2015-12-15

    Analytical electron microscopy has revealed the structure of particles that were synthesized by chemical reaction of GeO{sub 2} with NaBH{sub 4} in the basic solution including graphitic carbon nitride (g-C{sub 3}N{sub 4}) powders. The g-C{sub 3}N{sub 4} was arranged by recrystallization of melamine at 600 °C under N{sub 2} gas atmosphere. The samples were dried at 60 °C or 180 °C for 4 h. The g-C{sub 3}N{sub 4} was observed as lamellae of several ten nm or less in size and had an amorphous-like structure with a distorted lattice in an area as small as a few hundred pm in size. The reaction product was Ge(O) particles as fine as several nm in size and composed of Ge and O atoms. Most of the particles must be of GeO{sub 2−x} with the amorphous-like structure that has also a distorted lattice in an area of a few hundred pm in size. In the sample dried at 60 °C, the particles were found to be dispersed in a wide area on the g-C{sub 3}N{sub 4} lamella. It is hard to recognize those particles in TEM images. The particles in the sample dried at 180 °C became larger and were easily observed as isolated lumps. Hence, these powders can be regarded as GeO{sub 2}/g-C{sub 3}N{sub 4} or Ge/GeO{sub 2}/g-C{sub 3}N{sub 4} nanocomposites, and expected to be applicable to anode materials for high energy Li-ion batteries due to Ge catalysis effect, accordingly. - Graphical abstract: STEM analysis of Ge(O)/(graphitic carbon nitride) nanocomposite powder. - Highlights: • Graphitic (g)-C{sub 3}N{sub 4} powder was prepared at 600 °C by recrystallization of melamine. • Ge(O) was prepared by chemical reaction in a solution including the g-C{sub 3}N{sub 4} powders. • The products can be regarded as GeO{sub 2}/g-C{sub 3}N{sub 4} or Ge/GeO{sub 2}/g-C{sub 3}N{sub 4} nanocomposites. • GeO{sub 2} was amorphous several-nm particles and g-C{sub 3}N{sub 4} was amorphous lamella of several 10 nm in size. • We expect them to be applicable for high energy Li-ion battery anode

  3. Magnetooptical properties of iron based Heusler alloy epitaxial films on Ge(111)

    Science.gov (United States)

    Maeda, Yoshihito; Ikeda, Tatsuya; Ichikawa, Takayuki; Nakajima, Takahito; Matsukura, Bui; Sadoh, Taizoh; Miyao, Masanobu

    We have examined the LMOKE of some Heusler alloy films Fe4Si, Fe3Si, Fe2CoSi, Fe2MnSi (21 at and 9 at.%Mn), Co2FeSi epitaxially grown on Ge(111) and found that Fe3Si, Fe4Si and Fe2CoSi films have larger Kerr rotation and smaller coercive fields than the amorphous Fe film and that they may be promising materials for magnetophotonic applications.

  4. Studies of hydrogenated amorphous silicon

    Energy Technology Data Exchange (ETDEWEB)

    Bishop, S G; Carlos, W E

    1984-07-01

    This report discusses the results of probing the defect structure and bonding of hydrogenated amorphous silicon films using both nuclear magnetic resonance (NMR) and electron spin resonance (ESR). The doping efficiency of boron in a-Si:H was found to be less than 1%, with 90% of the boron in a threefold coordinated state. On the other hand, phosphorus NMR chemical shift measurements yielded a ration of threefold to fourfold P sites of roughly 4 to 1. Various resonance lines were observed in heavily boron- and phosphorus-doped films and a-SiC:H alloys. These lines were attributed to band tail states on twofold coordinated silicon. In a-SiC:H films, a strong resonance was attributed to dangling bonds on carbon atoms. ESR measurements on low-pressure chemical-vapor-deposited (LPCVD) a-Si:H were performed on samples. The defect density in the bulk of the films was 10/sup 17//cc with a factor of 3 increase at the surface of the sample. The ESR spectrum of LPCVD-prepared films was not affected by prolonged exposure to strong light. Microcrystalline silicon samples were also examined. The phosphorus-doped films showed a strong signal from the crystalline material and no resonance from the amorphous matrix. This shows that phosphorus is incorporated in the crystals and is active as a dopant. No signal was recorded from the boron-doped films.

  5. Poorer sustained attention in bipolar I than bipolar II disorder

    Directory of Open Access Journals (Sweden)

    Chen Shih-Heng

    2010-02-01

    Full Text Available Abstract Background Nearly all information processing during cognitive processing takes place during periods of sustained attention. Sustained attention deficit is among the most commonly reported impairments in bipolar disorder (BP. The majority of previous studies have only focused on bipolar I disorder (BP I, owing to underdiagnosis or misdiagnosis of bipolar II disorder (BP II. With the refinement of the bipolar spectrum paradigm, the goal of this study was to compare the sustained attention of interepisode patients with BP I to those with BP II. Methods In all, 51 interepisode BP patients (22 with BP I and 29 with BP II and 20 healthy controls participated in this study. The severity of psychiatric symptoms was assessed by the 17-item Hamilton Depression Rating Scale and the Young Mania Rating Scale. All participants undertook Conners' Continuous Performance Test II (CPT-II to evaluate sustained attention. Results After controlling for the severity of symptoms, age and years of education, BP I patients had a significantly longer reaction times (F(2,68 = 7.648, P = 0.001, worse detectability (d' values (F(2,68 = 6.313, P = 0.003 and more commission errors (F(2,68 = 6.182, P = 0.004 than BP II patients and healthy controls. BP II patients and controls scored significantly higher than BP I patients for d' (F = 6.313, P = 0.003. No significant difference was found among the three groups in omission errors and no significant correlations were observed between CPT-II performance and clinical characteristics in the three groups. Conclusions These findings suggested that impairments in sustained attention might be more representative of BP I than BP II after controlling for the severity of symptoms, age, years of education and reaction time on the attentional test. A longitudinal follow-up study design with a larger sample size might be needed to provide more information on chronological sustained attention deficit in BP patients, and to illustrate

  6. Swimming in Deep Water: Childhood Bipolar Disorder

    Science.gov (United States)

    Senokossoff, Gwyn W.; Stoddard, Kim

    2009-01-01

    The authors focused on one parent's struggles in finding a diagnosis and intervention for a child who had bipolar disorder. The authors explain the process of identification, diagnosis, and intervention of a child who had bipolar disorder. In addition to the personal story, the authors provide information on the disorder and outline strategies…

  7. Bipolar disorder diagnosis: challenges and future directions

    Science.gov (United States)

    Phillips, Mary L; Kupfer, David J

    2018-01-01

    Bipolar disorder refers to a group of affective disorders, which together are characterised by depressive and manic or hypomanic episodes. These disorders include: bipolar disorder type I (depressive and manic episodes: this disorder can be diagnosed on the basis of one manic episode); bipolar disorder type II (depressive and hypomanic episodes); cyclothymic disorder (hypomanic and depressive symptoms that do not meet criteria for depressive episodes); and bipolar disorder not otherwise specified (depressive and hypomanic-like symptoms that do not meet the diagnostic criteria for any of the aforementioned disorders). Bipolar disorder type II is especially difficult to diagnose accurately because of the difficulty in differentiation of this disorder from recurrent unipolar depression (recurrent depressive episodes) in depressed patients. The identification of objective biomarkers that represent pathophysiologic processes that differ between bipolar disorder and unipolar depression can both inform bipolar disorder diagnosis and provide biological targets for the development of new and personalised treatments. Neuroimaging studies could help the identification of biomarkers that differentiate bipolar disorder from unipolar depression, but the problem in detection of a clear boundary between these disorders suggests that they might be better represented as a continuum of affective disorders. Innovative combinations of neuroimaging and pattern recognition approaches can identify individual patterns of neural structure and function that accurately ascertain where a patient might lie on a behavioural scale. Ultimately, an integrative approach, with several biological measurements using different scales, could yield patterns of biomarkers (biosignatures) to help identify biological targets for personalised and new treatments for all affective disorders. PMID:23663952

  8. Transient Stuttering in Catatonic Bipolar Patients

    Directory of Open Access Journals (Sweden)

    Anthony B. Joseph

    1991-01-01

    Full Text Available Two cases of transient stuttering occurring in association with catatonia and bipolar disorder are described. Affective decompensation has been associated with lateralized cerebral dysfunction, and it is hypothesized that in some bipolar catatonic patients a concomitant disorder of the lateralization of language function may lead to a variety of clinical presentations including aphasia, mutism, and stuttering.

  9. Cognitive behavioral therapy for bipolar disorders

    OpenAIRE

    Lotufo Neto, Francisco

    2004-01-01

    Descrição dos objetivos e principais técnicas da terapia comportamental cognitiva usadas para a psicoterapia das pessoas com transtorno bipolar.Objectives and main techniques of cognitive behavior therapy for the treatment of bipolar disorder patients are described.

  10. NO signaling in retinal bipolar cells.

    Science.gov (United States)

    Agurto, A; Vielma, A H; Cadiz, B; Couve, E; Schmachtenberg, O

    2017-08-01

    Nitric oxide (NO) is a neuromodulator involved in physiological and pathological processes in the retina. In the inner retina, a subgroup of amacrine cells have been shown to synthesize NO, but bipolar cells remain controversial as NO sources. This study correlates NO synthesis in dark-adapted retinas, through labeling with the NO marker DAF-FM, with neuronal nitric oxide synthase (nNOS) and inducible NOS expression, and presence of the NO receptor soluble guanylate cyclase in bipolar cells. NO containing bipolar cells were morphologically identified by dialysis of DAF fluorescent cells with intracellular dyes, or by DAF labeling followed by immunohistochemistry for nNOS and other cellular markers. DAF fluorescence was observed in all types of bipolar cells that could be identified, but the most intense DAF fluorescence was observed in bipolar cells with severed processes, supporting pathological NO signaling. Among nNOS expressing bipolar cells, type 9 was confirmed unequivocally, while types 2, 3a, 3b, 4, 5, 7, 8 and the rod bipolar cell were devoid of this enzyme. These results establish specific bipolar cell types as NO sources in the inner retina, and support the involvement of NO signaling in physiological and pathological processes in the inner retina. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Thermoelectric Properties of Nanograined Si-Ge-Au Thin Films Grown by Molecular Beam Deposition

    Science.gov (United States)

    Nishino, Shunsuke; Ekino, Satoshi; Inukai, Manabu; Omprakash, Muthusamy; Adachi, Masahiro; Kiyama, Makoto; Yamamoto, Yoshiyuki; Takeuchi, Tsunehiro

    2017-11-01

    Conditions to achieve extremely large Seebeck coefficient and extremely small thermal conductivity in Si-Ge-Au thin films formed of nanosized grains precipitated in amorphous matrix have been investigated. We employed molecular beam deposition to prepare Si1-x Ge x Au y thin films on sapphire substrate. The deposited films were annealed under nitrogen gas atmosphere at 300°C to 500°C for 15 min to 30 min. Nanocrystals dispersed in amorphous matrix were clearly observed by transmission electron microscopy. We did not observe anomalously large Seebeck coefficient, but very low thermal conductivity of nearly 1.0 W K-1 m-1 was found at around 0.2 thermal conductivity was well accounted for by the compositional dependence of the mixing entropy. Some of these values agree exactly with the amorphous limit predicted by theoretical calculations. The smallest lattice thermal conductivity found for the present samples is lower than that of nanostructured Si-Ge bulk material for which dimensionless figure of merit of ZT ≈ 1 was reported at high temperature.

  12. Effects of carbon on phosphorus diffusion in SiGe:C and the implications on phosphorus diffusion mechanisms

    International Nuclear Information System (INIS)

    Lin, Yiheng; Xia, Guangrui; Yasuda, Hiroshi; Wise, Rick; Schiekofer, Manfred; Benna, Bernhard

    2014-01-01

    The use of carbon (C) in SiGe base layers is an important approach to control the base layer dopant phosphorus (P) diffusion and thus enhance PNP heterojunction bipolar transistor (HBT) performance. This work quantitatively investigated the carbon impacts on P diffusion in Si 0.82 Ge 0.18 :C and Si:C under rapid thermal anneal conditions. The carbon molar fraction is up to 0.32%. The results showed that the carbon retardation effect on P diffusion is less effective for Si 0.82 Ge 0.18 :C than for Si:C. In Si 0.82 Ge 0.18 :C, there is an optimum carbon content at around 0.05% to 0.1%, beyond which more carbon incorporation does not retard P diffusion any more. This behavior is different from the P diffusion behavior in Si:C and the B in Si:C and low Ge SiGe:C, which can be explained by the decreased interstitial-mediated diffusion fraction f I P, SiGe to 95% as Ge content increases to 18%. Empirical models were established to calculate the time-averaged point defect concentrations and effective diffusivities as a function of carbon and was shown to agree with previous studies on boron, phosphorus, arsenic and antimony diffusion with carbon.

  13. Structural morphology of amorphous conducting carbon film

    Indian Academy of Sciences (India)

    Unknown

    in nanotubes and sp3 rich amorphous carbons for their application in field emission, device application, etc in- vestigations on sp2 rich amorphous carbon forms are very few. Though DLC films have potential application in field emission (FE) due to their low threshold voltage, the carbon centres, which are believed to play ...

  14. Towards upconversion for amorphous silicon solar cells

    NARCIS (Netherlands)

    de Wild, J.; Meijerink, A.; Rath, J.K.; van Sark, W.G.J.H.M.; Schropp, R.E.I.

    2010-01-01

    Upconversion of subbandgap light of thin film single junction amorphous silicon solar cells may enhance their performance in the near infrared (NIR). In this paper we report on the application of the NIR–vis upconverter β-NaYF4:Yb3+(18%) Er3+(2%) at the back of an amorphous silicon solar cell in

  15. Film adhesion in amorphous silicon solar cells

    Indian Academy of Sciences (India)

    TECS

    flexible triple junction, amorphous silicon solar cells. At the Malaysia Energy Centre (MEC), we fabricated triple junction amorphous silicon solar cells (up to 12⋅7% efficiency (Wang et al 2002)) and laser-interconnected modules on steel, glass and polyimide substrates. A major issue encountered is the adhesion of thin film ...

  16. Colors and the evolution of amorphous galaxies

    International Nuclear Information System (INIS)

    Gallagher, J.S. III; Hunter, D.A.

    1987-01-01

    UBVRI and H-alpha photometric observations are presented for 16 amorphous galaxies and a comparison sample of Magellanic irregular (Im) and Sc spiral galaxies. These data are analyzed in terms of star-formation rates and histories in amorphous galaxies. Amorphous galaxies have mean global colors and star-formation rates per unit area that are similar to those in giant Im systems, despite differences in spatial distributions of star-forming centers in these two galactic structural classes. Amorphous galaxies differ from giant Im systems in having somewhat wider scatter in relationships between B - V and U - B colors, and between U - B and L(H-alpha)/L(B). This scatter is interpreted as resulting from rapid variations in star-formation rates during the recent past, which could be a natural consequence of the concentration of star-forming activity into centrally located, supergiant young stellar complexes in many amorphous galaxies. While the unusual spatial distribution and intensity of star formation in some amorphous galaxies is due to interactions with other galaxies, several amorphous galaxies are relatively isolated and thus the processes must be internal. The ultimate evolutionary fate of rapidly evolving amorphous galaxies remains unknown. 77 references

  17. Amorphization of ice under mechanical stresses

    Science.gov (United States)

    Bordonskii, G. S.; Krylov, S. D.

    2017-11-01

    The dielectric parameters of freshly produced freshwater ice in the microwave range are investigated. It is established that this kind of ice contains a noticeable amount of amorphous ice. Its production is associated with plastic deformation under mechanical stresses. An assessment of the dielectric-permeability change caused by amorphous ice in the state of a slowly flowing medium is given.

  18. Electron beam recrystallization of amorphous semiconductor materials

    Science.gov (United States)

    Evans, J. C., Jr.

    1968-01-01

    Nucleation and growth of crystalline films of silicon, germanium, and cadmium sulfide on substrates of plastic and glass were investigated. Amorphous films of germanium, silicon, and cadmium sulfide on amorphous substrates of glass and plastic were converted to the crystalline condition by electron bombardment.

  19. Photoexcitation-induced processes in amorphous semiconductors

    International Nuclear Information System (INIS)

    Singh, Jai

    2005-01-01

    Theories for the mechanism of photo-induced processes of photodarkening (PD), volume expansion (VE) in amorphous chalcogenides are presented. Rates of spontaneous emission of photons by radiative recombination of excitons in amorphous semiconductors are also calculated and applied to study the excitonic photoluminescence in a-Si:H. Results are compared with previous theories

  20. Analytical theory of noncollinear amorphous metallic magnetism

    International Nuclear Information System (INIS)

    Kakehashi, Y.; Uchida, T.

    2001-01-01

    Analytical theory of noncollinear magnetism in amorphous metals is proposed on the basis of the Gaussian model for the distribution of the interatomic distance and the saddle-point approximation. The theory removes the numerical difficulty in the previous theory based on the Monte-Carlo sampling method, and reasonably describes the magnetic properties of amorphous transition metals

  1. Thyroid Functions and Bipolar Affective Disorder

    Directory of Open Access Journals (Sweden)

    Subho Chakrabarti

    2011-01-01

    Full Text Available Accumulating evidence suggests that hypothalamo-pituitary-thyroid (HPT axis dysfunction is relevant to the pathophysiology and clinical course of bipolar affective disorder. Hypothyroidism, either overt or more commonly subclinical, appears to the commonest abnormality found in bipolar disorder. The prevalence of thyroid dysfunction is also likely to be greater among patients with rapid cycling and other refractory forms of the disorder. Lithium-treatment has potent antithyroid effects and can induce hypothyroidism or exacerbate a preexisting hypothyroid state. Even minor perturbations of the HPT axis may affect the outcome of bipolar disorder, necessitating careful monitoring of thyroid functions of patients on treatment. Supplementation with high dose thyroxine can be considered in some patients with treatment-refractory bipolar disorder. Neurotransmitter, neuroimaging, and genetic studies have begun to provide clues, which could lead to an improved understanding of the thyroid-bipolar disorder connection, and more optimal ways of managing this potentially disabling condition.

  2. Diagnostic stability in pediatric bipolar disorder

    DEFF Research Database (Denmark)

    Vedel Kessing, Lars; Vradi, Eleni; Andersen, Per Kragh

    2015-01-01

    BACKGROUND: The diagnostic stability of pediatric bipolar disorder has not been investigated previously. The aim was to investigate the diagnostic stability of the ICD-10 diagnosis of pediatric mania/bipolar disorder.METHODS: All patients below 19 years of age who got a diagnosis of mania/bipolar...... disorder at least once in a period from 1994 to 2012 at psychiatric inpatient or outpatient contact in Denmark were identified in a nationwide register.RESULTS: Totally, 354 children and adolescents got a diagnosis of mania/bipolar disorder at least once; a minority, 144 patients (40.7%) got the diagnosis...... at the first contact whereas the remaining patients (210; 59.3%) got the diagnosis at later contacts before age 19. For the latter patients, the median time elapsed from first treatment contact with the psychiatric service system to the first diagnosis with a manic episode/bipolar disorder was nearly 1 year...

  3. 2017 Bipolar Plate Workshop Summary Report

    Energy Technology Data Exchange (ETDEWEB)

    Kopasz, John P. [Argonne National Lab. (ANL), Argonne, IL (United States); Benjamin, Thomas G. [Argonne National Lab. (ANL), Argonne, IL (United States); Schenck, Deanna [Argonne National Lab. (ANL), Argonne, IL (United States)

    2017-08-17

    The Bipolar Plate (BP) Workshop was held at USCAR1 in Southfield, Michigan on February 14, 2017 and included 63 participants from industry, government agencies, universities, and national laboratories with expertise in the relevant fields. The objective of the workshop was to identify research and development (R&D) needs, in particular early-stage R&D, for bipolar plates for polymer electrolyte membrane (PEM) fuel cells for transportation applications. The focus of the workshop was on materials, manufacturing, and design aspects of bipolar plates with the goal of meeting DOE’s 2020 bipolar plate targets. Of special interest was the cost target of ≤$3/kW for the bipolar plate.

  4. Si, Ge and SiGe wires for sensor application

    International Nuclear Information System (INIS)

    Druzhinin, A.A.; Khoverko, Yu.M.; Ostrovskii, I.P.; Nichkalo, S.I.; Nikolaeva, A.A.; Konopko, L.A.; Stich, I.

    2011-01-01

    Resistance and magnetoresistance of Si, Ge and Si-Ge micro- and nanowires were studied in temperature range 4,2-300 K at magnetic fields up to 14 T. The wires diameters range from 200 nm to 20 μm. Ga-In gates were created to wires and ohmic I-U characteristics were observed in all temperature range. It was found high elastic strain for Ge nanowires (of about 0,7%) as well as high magnitude of magnetoresistance (of about 250% at 14 T), which was used to design multifunctional sensor of simultaneous measurements of strain and magnetic field intensity. (authors)

  5. Nanofluidic diode and bipolar transistor.

    Science.gov (United States)

    Daiguji, Hirofumi; Oka, Yukiko; Shirono, Katsuhiro

    2005-11-01

    Theoretical modeling of ionic distribution and transport in a nanochannel containing a surface charge on its wall, 30 nm high and 5 microm long, suggests that ionic current can be controlled by locally modifying the surface charge density through a gate electrode, even if the electrical double layers are not overlapped. When the surface charge densities at the right and left halves of a channel are the same absolute value but of different signs, this could form the basis of a nanofluidic diode. When the surface charge density at the middle part of a channel is modified, this could form the basis of a nanofluidic bipolar transistor.

  6. Solid-state diffusion in amorphous zirconolite

    Energy Technology Data Exchange (ETDEWEB)

    Yang, C.; Dove, M. T.; Trachenko, K. [School of Physics and Astronomy, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom); Zarkadoula, E. [School of Physics and Astronomy, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom); Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6138 (United States); Todorov, I. T. [STFC Daresbury Laboratory, Warrington WA4 1EP (United Kingdom); Geisler, T. [Steinmann-Institut für Geologie, Mineralogie und Paläontologie, University of Bonn, D-53115 Bonn (Germany); Brazhkin, V. V. [Institute for High Pressure Physics, RAS, 142190 Moscow (Russian Federation)

    2014-11-14

    We discuss how structural disorder and amorphization affect solid-state diffusion, and consider zirconolite as a currently important case study. By performing extensive molecular dynamics simulations, we disentangle the effects of amorphization and density, and show that a profound increase of solid-state diffusion takes place as a result of amorphization. Importantly, this can take place at the same density as in the crystal, representing an interesting general insight regarding solid-state diffusion. We find that decreasing the density in the amorphous system increases pre-factors of diffusion constants, but does not change the activation energy in the density range considered. We also find that atomic species in zirconolite are affected differently by amorphization and density change. Our microscopic insights are relevant for understanding how solid-state diffusion changes due to disorder and for building predictive models of operation of materials to be used to encapsulate nuclear waste.

  7. Ge-on-Si optoelectronics

    Energy Technology Data Exchange (ETDEWEB)

    Liu Jifeng, E-mail: Jifeng.Liu@Dartmouth.edu [Thayer School of Engineering, Dartmouth College, Hanover, NH 03755 (United States); Camacho-Aguilera, Rodolfo; Bessette, Jonathan T.; Sun, Xiaochen [Microphotonics Center, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Wang Xiaoxin [Thayer School of Engineering, Dartmouth College, Hanover, NH 03755 (United States); Cai Yan; Kimerling, Lionel C.; Michel, Jurgen [Microphotonics Center, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)

    2012-02-01

    Electronic-photonic synergy has become an increasingly clear solution to enhance the bandwidth and improve the energy efficiency of information systems. Monolithic integration of optoelectronic devices is the ideal solution for large-scale electronic-photonic synergy. Due to its pseudo-direct gap behavior in optoelectronic properties and compatibility with Si electronics, epitaxial Ge-on-Si has become an attractive solution for monolithic optoelectronics. In this paper we will review recent progress in Ge-on-Si optoelectronics, including photodetectors, electroabsorption modulators, and lasers. The performance of these devices has been enhanced by band-engineering such as tensile strain and n-type doping, which transforms Ge towards a direct gap material. Selective growth reduces defect density and facilitates monolithic integration at the same time. Ge-on-Si photodetectors have approached or exceeded the performance of their III-V counterparts, with bandwidth-efficiency product > 30 GHz for p-i-n photodiodes and bandwidth-gain product > 340 GHz for avalanche photodiodes. Enhanced Franz-Keldysh effect in tensile-strained Ge offers ultralow energy photonic modulation with < 30 fJ/bit energy consumption and > 100 GHz intrinsic bandwidth. Room temperature optically-pumped lasing as well as electroluminescence has also been achieved from the direct gap transition of band-engineered Ge-on-Si waveguides. These results indicate that band-engineered Ge-on-Si is promising to achieve monolithic active optoelectronic devices on a Si platform.

  8. Locomotion of Amorphous Surface Robots

    Science.gov (United States)

    Bradley, Arthur T. (Inventor)

    2016-01-01

    An amorphous robot includes a compartmented bladder containing fluid, a valve assembly, and an outer layer encapsulating the bladder and valve assembly. The valve assembly draws fluid from a compartment(s) and discharges the drawn fluid into a designated compartment to displace the designated compartment with respect to the surface. Another embodiment includes elements each having a variable property, an outer layer that encapsulates the elements, and a control unit. The control unit energizes a designated element to change its variable property, thereby moving the designated element. The elements may be electromagnetic spheres with a variable polarity or shape memory polymers with changing shape and/or size. Yet another embodiment includes an elongated flexible tube filled with ferrofluid, a moveable electromagnet, an actuator, and a control unit. The control unit energizes the electromagnet and moves the electromagnet via the actuator to magnetize the ferrofluid and lengthen the flexible tube.

  9. Cryogenic ultra-low-noise SiGe transistor amplifier.

    Science.gov (United States)

    Ivanov, B I; Trgala, M; Grajcar, M; Il'ichev, E; Meyer, H-G

    2011-10-01

    An ultra-low-noise one-stage SiGe heterojunction bipolar transistor amplifier was designed for cryogenic temperatures and a frequency range of 10 kHz-100 MHz. A noise temperature T(N) ≈ 1.4 K was measured at an ambient temperature of 4.2 K at frequencies between 100 kHz and 100 MHz for a source resistance of ~50 Ω. The voltage gain of the amplifier was 25 dB at a power consumption of 720 μW. The input voltage noise spectral density of the amplifier is about 35 pV/√Hz. The low noise resistance and power consumption makes the amplifier suitable for readout of resistively shunted DC SQUID magnetometers and amplifiers.

  10. DeepBipolar: Identifying genomic mutations for bipolar disorder via deep learning.

    Science.gov (United States)

    Laksshman, Sundaram; Bhat, Rajendra Rana; Viswanath, Vivek; Li, Xiaolin

    2017-09-01

    Bipolar disorder, also known as manic depression, is a brain disorder that affects the brain structure of a patient. It results in extreme mood swings, severe states of depression, and overexcitement simultaneously. It is estimated that roughly 3% of the population of the United States (about 5.3 million adults) suffers from bipolar disorder. Recent research efforts like the Twin studies have demonstrated a high heritability factor for the disorder, making genomics a viable alternative for detecting and treating bipolar disorder, in addition to the conventional lengthy and costly postsymptom clinical diagnosis. Motivated by this study, leveraging several emerging deep learning algorithms, we design an end-to-end deep learning architecture (called DeepBipolar) to predict bipolar disorder based on limited genomic data. DeepBipolar adopts the Deep Convolutional Neural Network (DCNN) architecture that automatically extracts features from genotype information to predict the bipolar phenotype. We participated in the Critical Assessment of Genome Interpretation (CAGI) bipolar disorder challenge and DeepBipolar was considered the most successful by the independent assessor. In this work, we thoroughly evaluate the performance of DeepBipolar and analyze the type of signals we believe could have affected the classifier in distinguishing the case samples from the control set. © 2017 Wiley Periodicals, Inc.

  11. Comparison of depressive episodes in bipolar disorder and in major depressive disorder within bipolar disorder pedigrees.

    Science.gov (United States)

    Mitchell, Philip B; Frankland, Andrew; Hadzi-Pavlovic, Dusan; Roberts, Gloria; Corry, Justine; Wright, Adam; Loo, Colleen K; Breakspear, Michael

    2011-10-01

    Although genetic epidemiological studies have confirmed increased rates of major depressive disorder among the relatives of people with bipolar affective disorder, no report has compared the clinical characteristics of depression between these two groups. To compare clinical features of depressive episodes across participants with major depressive disorder and bipolar disorder from within bipolar disorder pedigrees, and assess the utility of a recently proposed probabilistic approach to distinguishing bipolar from unipolar depression. A secondary aim was to identify subgroups within the relatives with major depression potentially indicative of 'genetic' and 'sporadic' subgroups. Patients with bipolar disorder types 1 and 2 (n = 246) and patients with major depressive disorder from bipolar pedigrees (n = 120) were assessed using the Diagnostic Interview for Genetic Studies. Logistic regression was used to identify distinguishing clinical features and assess the utility of the probabilistic approach. Hierarchical cluster analysis was used to identify subgroups within the major depressive disorder sample. Bipolar depression was characterised by significantly higher rates of psychomotor retardation, difficulty thinking, early morning awakening, morning worsening and psychotic features. Depending on the threshold employed, the probabilistic approach yielded a positive predictive value ranging from 74% to 82%. Two clusters within the major depressive disorder sample were found, one of which demonstrated features characteristic of bipolar depression, suggesting a possible 'genetic' subgroup. A number of previously identified clinical differences between unipolar and bipolar depression were confirmed among participants from within bipolar disorder pedigrees. Preliminary validation of the probabilistic approach in differentiating between unipolar and bipolar depression is consistent with dimensional distinctions between the two disorders and offers clinical utility in

  12. A YinYang bipolar fuzzy cognitive TOPSIS method to bipolar disorder diagnosis.

    Science.gov (United States)

    Han, Ying; Lu, Zhenyu; Du, Zhenguang; Luo, Qi; Chen, Sheng

    2018-05-01

    Bipolar disorder is often mis-diagnosed as unipolar depression in the clinical diagnosis. The main reason is that, different from other diseases, bipolarity is the norm rather than exception in bipolar disorder diagnosis. YinYang bipolar fuzzy set captures bipolarity and has been successfully used to construct a unified inference mathematical modeling method to bipolar disorder clinical diagnosis. Nevertheless, symptoms and their interrelationships are not considered in the existing method, circumventing its ability to describe complexity of bipolar disorder. Thus, in this paper, a YinYang bipolar fuzzy multi-criteria group decision making method to bipolar disorder clinical diagnosis is developed. Comparing with the existing method, the new one is more comprehensive. The merits of the new method are listed as follows: First of all, multi-criteria group decision making method is introduced into bipolar disorder diagnosis for considering different symptoms and multiple doctors' opinions. Secondly, the discreet diagnosis principle is adopted by the revised TOPSIS method. Last but not the least, YinYang bipolar fuzzy cognitive map is provided for the understanding of interrelations among symptoms. The illustrated case demonstrates the feasibility, validity, and necessity of the theoretical results obtained. Moreover, the comparison analysis demonstrates that the diagnosis result is more accurate, when interrelations about symptoms are considered in the proposed method. In a conclusion, the main contribution of this paper is to provide a comprehensive mathematical approach to improve the accuracy of bipolar disorder clinical diagnosis, in which both bipolarity and complexity are considered. Copyright © 2018 Elsevier B.V. All rights reserved.

  13. Can neuroimaging disentangle bipolar disorder?

    Science.gov (United States)

    Hozer, Franz; Houenou, Josselin

    2016-05-01

    Bipolar disorder heterogeneity is large, leading to difficulties in identifying neuropathophysiological and etiological mechanisms and hindering the formation of clinically homogeneous patient groups in clinical trials. Identifying markers of clinically more homogeneous groups would help disentangle BD heterogeneity. Neuroimaging may aid in identifying such groups by highlighting specific biomarkers of BD subtypes or clinical dimensions. We performed a systematic literature search of the neuroimaging literature assessing biomarkers of relevant BD phenotypes (type-I vs. II, presence vs. absence of psychotic features, suicidal behavior and impulsivity, rapid cycling, good vs. poor medication response, age at onset, cognitive performance and circadian abnormalities). Consistent biomarkers were associated with suicidal behavior, i.e. frontal/anterior alterations (prefrontal and cingulate grey matter, prefrontal white matter) in patients with a history of suicide attempts; and with cognitive performance, i.e. involvement of frontal and temporal regions, superior and inferior longitudinal fasciculus, right thalamic radiation, and corpus callosum in executive dysfunctions. For the other dimensions and sub-types studied, no consistent biomarkers were identified. Studies were heterogeneous both in methodology and outcome. Though theoretically promising, neuroimaging has not yet proven capable of disentangling subtypes and dimensions of bipolar disorder, due to high between-study heterogeneity. We issue recommendations for future studies. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Mn-doped Ge self-assembled quantum dots via dewetting of thin films

    Energy Technology Data Exchange (ETDEWEB)

    Aouassa, Mansour, E-mail: mansour.aouassa@yahoo.fr [LMON, Faculté des Sciences de Monastir, Avenue de l’environnement Monastir 5019 (Tunisia); Jadli, Imen [LMON, Faculté des Sciences de Monastir, Avenue de l’environnement Monastir 5019 (Tunisia); Bandyopadhyay, Anup [Department of Mechanical Engineering, Texas A& M University, College Station, TX 77843 (United States); Kim, Sung Kyu [Center for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS), Yuseong-daero 1689-gil, Yuseong-gu, Daejeon (Korea, Republic of); Department of Materials Science and Engineering, KAIST 291 Daehak-ro, Yuseong-gu, Daejeon (Korea, Republic of); Karaman, Ibrahim [Department of Mechanical Engineering, Texas A& M University, College Station, TX 77843 (United States); Lee, Jeong Yong [Center for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS), Yuseong-daero 1689-gil, Yuseong-gu, Daejeon (Korea, Republic of); Department of Materials Science and Engineering, KAIST 291 Daehak-ro, Yuseong-gu, Daejeon (Korea, Republic of)

    2017-03-01

    Highlights: • We report the new fabrication approach for producing a self- assembled Mn dpoed Ge quantum dots (QDs) on SiO{sub 2} thin film with a Curie temperature above room temperature. These magnetic QDs are crystalline, monodisperse and have a well-defined shape and a controlled size. The investigation opens new routes for elaboration of self-assembled magnetic nanocrystals - Abstract: In this study, we demonstrate an original elaboration route for producing a Mn-doped Ge self-assembled quantum dots on SiO{sub 2} thin layer for MOS structure. These magnetic quantum dots are elaborated using dewetting phenomenon at solid state by Ultra-High Vacuum (UHV) annealing at high temperature of an amorphous Ge:Mn (Mn: 40%) nanolayer deposed at very low temperature by high-precision Solid Source Molecular Beam Epitaxy on SiO{sub 2} thin film. The size of quantum dots is controlled with nanometer scale precision by varying the nominal thickness of amorphous film initially deposed. The magnetic properties of the quantum-dots layer have been investigated by superconducting quantum interference device (SQUID) magnetometry. Atomic force microscopy (AFM), x-ray energy dispersive spectroscopy (XEDS) and transmission electron microscopy (TEM) were used to examine the nanostructure of these materials. Obtained results indicate that GeMn QDs are crystalline, monodisperse and exhibit a ferromagnetic behavior with a Curie temperature (TC) above room temperature. They could be integrated into spintronic technology.

  15. Brief Report: A Family Risk Study Exploring Bipolar Spectrum Problems and Cognitive Biases in Adolescent Children of Bipolar Parents

    Science.gov (United States)

    Espie, Jonathan; Jones, Steven H.; Vance, Yvonne H.; Tai, Sara J.

    2012-01-01

    Children of parents with bipolar disorder are at increased risk of bipolar spectrum diagnoses. This cross-sectional study explores cognitive factors in the prediction of vulnerability to bipolar disorder. Adolescents at high-risk (with a parent with bipolar disorder; n = 23) and age and gender matched adolescents (n = 24) were recruited. Parent…

  16. Lower switch rate in depressed patients with bipolar II than bipolar I disorder treated adjunctively with second-generation antidepressants

    NARCIS (Netherlands)

    Altshuler, LL; Suppes, T; Nolen, WA; Leverich, G; Keck, PE; Frye, MA; Kupka, R; McElroy, SL; Grunze, H; Kitchen, CMR; Post, R; Black, D.O.

    Objectives: The authors compared the switch rate into hypomania/mania in depressed patients treated with second-generation antidepressants who had either bipolar I or bipolar II disorder. Method: In a 10-week trial, 184 outpatients with bipolar depression (134 with bipolar I disorder, 48 with

  17. In situ transmission electron microscopy analysis of electron beam induced crystallization of amorphous marks in phase-change materials

    International Nuclear Information System (INIS)

    Kaiser, M.; Pieterson, L. van; Verheijen, M.A.

    2004-01-01

    Crystallization of amorphous data marks in crystalline Ga 15 Sb 85 and Ge,In doped SbTe phase-change material was studied in situ in a Transmission Electron Microscope (TEM). Electron irradiation induced crystallization was obtained at room temperature using a 120 kV beam. In general, electron beam (e - beam) induced crystallization started from the amorphous-crystalline interface and was growth dominated for both materials. A dependence of growth velocity on electron beam intensity and crystal direction was observed. A comparison with laser-crystallized amorphous marks was made. For laser-induced crystallization also crystal growth from the amorphous-crystalline interface was seen. However, differences in morphology between the e - -beam and laser-recrystallized data marks of the GaSb phase-change material were observed. The electron beam erased data marks contained crystals with (extremely) large periodicities found in three dimensions. For the Ge,In doped SbTe phase-change material identical morphologies were observed for the e - -beam and laser-recrystallized data marks. Both methods that induce crystallization displayed a rhombohedral Sb structure, the same structure as the laser-crystallized surroundings

  18. Analysis of threshold current of uniaxially tensile stressed bulk Ge and Ge/SiGe quantum well lasers.

    Science.gov (United States)

    Jiang, Jialin; Sun, Junqiang; Gao, Jianfeng; Zhang, Ruiwen

    2017-10-30

    We propose and design uniaxially tensile stressed bulk Ge and Ge/SiGe quantum well lasers with the stress along direction. The micro-bridge structure is adapted for introducing uniaxial stress in Ge/SiGe quantum well. To enhance the fabrication tolerance, full-etched circular gratings with high reflectivity bandwidths of ~500 nm are deployed in laser cavities. We compare and analyze the density of state, the number of states between Γ- and L-points, the carrier injection efficiency, and the threshold current density for the uniaxially tensile stressed bulk Ge and Ge/SiGe quantum well lasers. Simulation results show that the threshold current density of the Ge/SiGe quantum well laser is much higher than that of the bulk Ge laser, even combined with high uniaxial tensile stress owing to the larger number of states between Γ- and L- points and extremely low carrier injection efficiency. Electrical transport simulation reveals that the reduced effective mass of the hole and the small conduction band offset cause the low carrier injection efficiency of the Ge/SiGe quantum well laser. Our theoretical results imply that unlike III-V material, uniaxially tensile stressed bulk Ge outperforms a Ge/SiGe quantum well with the same strain level and is a promising approach for Si-compatible light sources.

  19. Violence in schizophrenia and bipolar disorder.

    Science.gov (United States)

    Volavka, Jan

    2013-03-01

    Although most psychiatric patients are not violent, serious mental illness is associated with increased risk of violent behavior. Most of the evidence available pertains to schizophrenia and bipolar disorder. MEDLINE data base was searched for articles published between 1966 and November 2012 using the combination of key words 'schizophrenia' or 'bipolar disorder' with 'aggression' or 'violence'. For the treatment searches, generic names were used in combination with key words 'schizophrenia' or 'bipolar disorder' and 'aggression' No language constraint was applied. Only articles dealing with adults were included. The lists of references were searched manually to find additional articles. There were statistically significant increases of risk of violence in schizophrenia and in bipolar disorder in comparison with general population. The evidence suggests that the risk of violence is greater in bipolar disorder than in schizophrenia. Most of the violence in bipolar disorder occurs during the manic phase. The risk of violence in schizophrenia and bipolar disorder is increased by comorbid substance use disorder. Violence among adults with schizophrenia may follow at least two distinct pathways-one associated with antisocial conduct, and another associated with the acute psychopathology of schizophrenia. Clozapine is the most effective treatment of aggressive behavior in schizophrenia. Emerging evidence suggests that olanzapine may be the second line of treatment. Treatment adherence is of key importance. Non-pharmacological methods of treatment of aggression in schizophrenia and bipolar disorder are increasingly important. Cognitive behavioral approaches appear to be effective in cases where pharmacotherapy alone does not suffice. Violent behavior of patients with schizophrenia and bipolar disorder is a public health problem. Pharmacological and non-pharmacological approaches should be used to treat not only violent behavior, but also contributing comorbidities such

  20. <300> GeV team

    CERN Multimedia

    CERN PhotoLab

    1971-01-01

    The 300 GeV team had been assembled. In the photograph are Hans Horisberger, Clemens Zettler, Roy Billinge, Norman Blackburne, John Adams, Hans-Otto Wuster, Lars Persson, Bas de Raad, Hans Goebel, Simon Van der Meer.

  1. IBA study of SiGe/SiO{sub 2} nanostructured multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Barradas, Nuno P., E-mail: nunoni@ctn.ist.utl.pt [Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, E.N. 10 (ao km 139,7), 2695-066 Bobadela LRS (Portugal); Laboratório de Engenharia Nuclear, Instituto Superior Técnico, Universidade de Lisboa, E.N. 10 (ao km 139,7), 2695-066 Bobadela LRS (Portugal); Alves, E. [Associação Euratom/IST, Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Vieira, E.M.F. [Centre of Physics and Physics Department, University of Minho, 4710-057 Braga (Portugal); Parisini, A. [CNR-IMM Sezione di Bologna, via P. Gobetti 101, 40129 Bologna (Italy); Conde, O. [Physics Department and ICEMS, University of Lisbon, 1749-016 Lisboa (Portugal); Martín-Sánchez, J. [Laser Processing Group, Instituto de Óptica, CSIC, C/Serrano 121, 28006 Madrid (Spain); Rolo, A.G. [Centre of Physics and Physics Department, University of Minho, 4710-057 Braga (Portugal); Chahboun, A. [Centre of Physics and Physics Department, University of Minho, 4710-057 Braga (Portugal); FST Tanger, Physics Department, BP 416 Tanger (Morocco); Gomes, M.J.M. [Centre of Physics and Physics Department, University of Minho, 4710-057 Braga (Portugal)

    2014-07-15

    SiGe/SiO{sub 2} multilayers with layer thickness of 5 nm were deposited with RF magnetron sputtering. The as deposited samples had well defined SiGe amorphous layers. Different annealing treatments were made to promote the formation of SiGe nanocrystals. We report an ion beam analysis study with the Rutherford backscattering and elastic recoil analysis detection techniques, in order to determine the thickness and composition of the nanolayers, and gain insight into the evolution of the roughness of the layers. The results are correlated with other structural properties of the samples, as measured with complementary techniques such as grazing incidence X-ray diffraction annular dark field scanning transmission electron microscopy and high resolution transmission electron microscopy.

  2. Ferromagnetism in Mn-Implanted Epitaxially Grown Ge on Si(100)

    Energy Technology Data Exchange (ETDEWEB)

    Guchhait, S.; Jamil, M.; Ohldag, H.; Mehta, A.; Arenholz, E.; Lian, G.; Li Fatou, A.; Ferrer, D. A.; Markert, J. T.; Colombo, L.; Banerjee, S. K.

    2011-01-05

    We have studied ferromagnetism of Mn-implanted epitaxial Ge films on silicon. The Ge films were grown by ultrahigh vacuum chemical vapor deposition using a mixture of germane (GeH{sub 4}) and methylgermane (CH{sub 3}GeH{sub 3}) gases with a carbon concentration of less than 1 at. %, and observed surface rms roughness of 0.5 nm, as measured by atomic force microscopy. Manganese ions were implanted in epitaxial Ge films grown on Si (100) wafers to an effective concentration of 16, 12, 6, and 2 at. %. Superconducting quantum interference device measurements showed that only the three highest Mn concentration samples are ferromagnetic, while the fourth sample, with [Mn] = 2 at. %, is paramagnetic. X-ray absorption spectroscopy and x-ray magnetic circular dichroism measurements indicate that localized Mn moments are ferromagnetically coupled below the Curie temperature. Isothermal annealing of Mn-implanted Ge films with [Mn] = 16 at. % at 300 C for up to 1200 s decreases the magnetization but does not change the Curie temperature, suggesting that the amount of the magnetic phase slowly decreases with time at this anneal temperature. Furthermore, transmission electron microscopy and synchrotron grazing incidence x-ray diffraction experiments show that the Mn-implanted region is amorphous, and we believe that it is this phase that is responsible for the ferromagnetism. This is supported by our observation that high-temperature annealing leads to recrystallization and transformation of the material into a paramagnetic phase.

  3. In-situ crystallization of GeTeGaSb phase change memory stacked films

    Science.gov (United States)

    Velea, A.; Borca, C. N.; Socol, G.; Galca, A. C.; Grolimund, D.; Popescu, M.; van Bokhoven, J. A.

    2014-12-01

    Single and double layer phase change memory structures based on GeTe and GaSb thin films were deposited by pulsed laser deposition (PLD). Their crystallization behavior was studied using in-situ synchrotron techniques. Electrical resistance vs. temperature investigations, using the four points probe method, showed transition temperatures of 138 °C and 198 °C for GeTe and GaSb single films, respectively. It was found that after GeTe crystallization in the stacked films, Ga atoms from the GaSb layer diffused in the vacancies of the GeTe crystalline structure. Therefore, the crystallization temperature of the Sb-rich GaSb layer is decreased by more than 30 °C. Furthermore, at 210 °C, the antimony excess from GaSb films crystallizes as a secondary phase. At higher annealing temperatures, the crystalline Sb phase increased on the expense of GaSb crystalline phase which was reduced. Extended X-ray absorption fine structure (EXAFS) measurements at the Ga and Ge K-edges revealed changes in their local atomic environments as a function of the annealing temperature. Simulations unveil a tetrahedral configuration in the amorphous state and octahedral configuration in the crystalline state for Ge atoms, while Ga is four-fold coordinated in both as-deposited and annealed samples.

  4. Tratamento do transtorno bipolar: eutimia Bipolar disorder treatment: euthymia

    Directory of Open Access Journals (Sweden)

    Fábio Gomes de Matos e Souza

    2005-01-01

    Full Text Available O transtorno bipolar é um quadro complexo caracterizado por episódios de depressão, mania ou hipomania e fases assintomáticas. O tratamento visa ao controle de episódios agudos e prevenção de novos episódios. O tratamento farmacológico iniciou-se com o lítio. Até o momento, o lítio permanece como o tratamento com mais evidências favoráveis na fase de manutenção. Outros tratamentos demonstram eficácia nessa fase, como o valproato, a carbamazepina e os antipsicóticos atípicos. Dos antipsicóticos atípicos o mais estudado nesta fase do tratamento é a olanzapina. Mais estudos prospectivos são necessários para confirmar a ação profilática de novos agentes.Bipolar disorder is a complex disorder characterized by depression episodes, mania or hypomania and asymptomatic phases. The treatment aims at the control of acute episodes and prevention of new episodes. The pharmacological treatment was inaugurated with lithium. Until the moment, lithium remains as the treatment with more favorable evidences in the maintenance phase. Other treatments demonstrate efficacy in this phase, as valproate, carbamazepine and atypical antipsychotics. Of the atypical antipsychotics, the most studied in this phase of treatment is olanzapine. More prospective studies are necessary to confirm prophylactic action of new agents.

  5. Ionizing radiations simulation on bipolar components

    International Nuclear Information System (INIS)

    Montagner, X.

    1999-01-01

    This thesis presents the ionizing radiation effects on bipolar components and more specially their behavior facing the total dose. The first part is devoted to the radiation environments with a special attention to the spatial environments and new emergent environments. The specificities of bipolar components are then presented and their behavior facing the interactions. The physical mechanisms bound to the dose rate are also discussed. The second part presents a physical analysis of degradations induced by the cumulated dosimetry on bipolar components and simulation with the ATLAS code. The third part exposes an electric empirical simulation induced by the cumulated dose in static conditions. (A.L.B.)

  6. Bipolar Disorder and Early Affective Trauma.

    Science.gov (United States)

    de Codt, Aloise; Monhonval, Pauline; Bongaerts, Xavier; Belkacemi, Ikram; Tecco, Juan Martin

    2016-09-01

    Bipolar disorder is a chronic psychiatric disease with a high prevalence and is a major psychosocial and medical burden. The exact etiological pathways of bipolar disorder are not fully understood. Genetic factors are known to play an important role in the etiology of bipolar disorder. However, high rates of discordance among identical twins and a growing body of evidence that environmental factors such as early stress can influence the onset and course of psychiatric diseases underline the importance of additional etiological mechanisms of bipolar disorders. There has been little investigation about early trauma in bipolar disorder. The aim of this study was to review the literature on the association between early traumatic interactions like child neglect, mistreatment, abuse or early parental separation and the occurrence of bipolar disorder in adulthood or impact on the course of the disease. Studies investigating associations between child neglect, mistreatment, abuse or early parental separation and occurrence of bipolar disorder in adulthood or impact on the course of the disease were searched in the Pubmed database. More than 700 articles were sorted independently by two of the authors using predefined criteria. Only research articles, reviews and meta-analyses were selected for this review. 53 articles met the inclusion criteria. To date, four systematic reviews partially addressed our research question. Early trauma is more frequently found in the past of bipolar patients than in the general population. Studies support a harmful effect of childhood trauma on the course of bipolar disease, with more anxious, depressive or psychotic symptoms, an early age of onset and a worse prognosis. Early trauma is more often found in the past of bipolar adult patients than the general population and studies support a harmful effect of childhood trauma on the course of bipolar disease, with more anxious, depressive or psychotic symptoms, an early age of onset and a

  7. Cognitive Behavioral Therapy in Bipolar Disorder

    Directory of Open Access Journals (Sweden)

    Zeynep Mackali

    2011-12-01

    Full Text Available Bipolar disorder is an early-onset, chronic disorder. It impairs occupational, social, and family functioning, which makes learning to adapt living with the disorder and its treatment critically important. Therefore, it has now become common knowledge that psychosocial interventions are also necessary in the treatment of bipolar disorder adjunctive to pharmacotherapy. Thus, whichever psychosocial interventions are more effective in bipolar disorder is a crucial research question. In this article, cognitive-behavioral therapy, which is applied adjunctive to pharmacotherapy, will be addressed and the findings of research about the effectiveness of these applications will be reviewed.

  8. Sexuality and Sexual Dysfunctions in Bipolar Disorder

    Directory of Open Access Journals (Sweden)

    Zeynep Namli

    2016-12-01

    Full Text Available In the clinical course of bipolar disorder, there is a reduction in sexual will during depressive episodes and inappopriate sexual experiences and hypersexuality occurs during manic episodes. Up to now, studies focused on sexual side effects of drugs. Sexual violence, sexually transmitted diseases, contraception methods, unplanned pregnancies need to be assessed carefully in bipolar disorder patients. This review focused on sexuality and sexual dysfunctions in the course of bipolar disorder. [Psikiyatride Guncel Yaklasimlar - Current Approaches in Psychiatry 2016; 8(4.000: 309-320

  9. Photonic crystals, amorphous materials, and quasicrystals.

    Science.gov (United States)

    Edagawa, Keiichi

    2014-06-01

    Photonic crystals consist of artificial periodic structures of dielectrics, which have attracted much attention because of their wide range of potential applications in the field of optics. We may also fabricate artificial amorphous or quasicrystalline structures of dielectrics, i.e. photonic amorphous materials or photonic quasicrystals. So far, both theoretical and experimental studies have been conducted to reveal the characteristic features of their optical properties, as compared with those of conventional photonic crystals. In this article, we review these studies and discuss various aspects of photonic amorphous materials and photonic quasicrystals, including photonic band gap formation, light propagation properties, and characteristic photonic states.

  10. Progression along the Bipolar Spectrum: A Longitudinal Study of Predictors of Conversion from Bipolar Spectrum Conditions to Bipolar I and II Disorders

    Science.gov (United States)

    Alloy, Lauren B.; Urošević, Snežana; Abramson, Lyn Y.; Jager-Hyman, Shari; Nusslock, Robin; Whitehouse, Wayne G.; Hogan, Michael

    2011-01-01

    Little longitudinal research has examined progression to more severe bipolar disorders in individuals with “soft” bipolar spectrum conditions. We examine rates and predictors of progression to bipolar I and II diagnoses in a non-patient sample of college-age participants (n = 201) with high General Behavior Inventory scores and childhood or adolescent onset of “soft” bipolar spectrum disorders followed longitudinally for 4.5 years from the Longitudinal Investigation of Bipolar Spectrum (LIBS) project. Of 57 individuals with initial cyclothymia or bipolar disorder not otherwise specified (BiNOS) diagnoses, 42.1% progressed to a bipolar II diagnosis and 10.5% progressed to a bipolar I diagnosis. Of 144 individuals with initial bipolar II diagnoses, 17.4% progressed to a bipolar I diagnosis. Consistent with hypotheses derived from the clinical literature and the Behavioral Approach System (BAS) model of bipolar disorder, and controlling for relevant variables (length of follow-up, initial depressive and hypomanic symptoms, treatment-seeking, and family history), high BAS sensitivity (especially BAS Fun Seeking) predicted a greater likelihood of progression to bipolar II disorder, whereas early age of onset and high impulsivity predicted a greater likelihood of progression to bipolar I (high BAS sensitivity and Fun-Seeking also predicted progression to bipolar I when family history was not controlled). The interaction of high BAS and high Behavioral Inhibition System (BIS) sensitivities also predicted greater likelihood of progression to bipolar I. We discuss implications of the findings for the bipolar spectrum concept, the BAS model of bipolar disorder, and early intervention efforts. PMID:21668080

  11. 2D device-level simulation study of strained-Si pnp heterojunction bipolar transistors on virtual substrates

    Science.gov (United States)

    Jankovic, N. D.; O'Neill, A.

    2004-02-01

    A novel strained-Si pnp heterojunction bipolar transistor (HBT) design, suitable for virtual substrate technology, is proposed that is inherently free from the detrimental valence band barrier effects usually encountered in conventional SiGe pnp HBTs on silicon. It takes advantage of the heterojunction formed between a strained-Si layer and a relaxed SiGe buffer (virtual substrate), whose associated valence band offset appears favorable for minority hole transport at the base/collector junction. From two-dimensional (2D) numerical simulation, it is found that the newly proposed strained-Si pnp HBT substantially outperforms the equivalent BJT on a silicon substrate in terms of DC and high-frequency characteristics. A threefold increase in maximum current gain β, a fourfold improvement in peak ft and a 2.5 times increase in peak fmax are predicted for strained-Si pnp HBTs on a 50% Ge virtual substrate in comparison with identical conventional silicon pnp BJTs.

  12. Threshold switching in SiGeAsTeN chalcogenide glass prepared by As ion implantation into sputtered SiGeTeN film

    Science.gov (United States)

    Liu, Guangyu; Wu, Liangcai; Song, Zhitang; Liu, Yan; Li, Tao; Zhang, Sifan; Song, Sannian; Feng, Songlin

    2017-12-01

    A memory cell composed of a selector device and a storage device is the basic unit of phase change memory. The threshold switching effect, main principle of selectors, is a universal phenomenon in chalcogenide glasses. In this work, we put forward a safe and controllable method to prepare a SiGeAsTeN chalcogenide film by implanting As ions into sputtered SiGeTeN films. For the SiGeAsTeN material, the phase structure maintains the amorphous state, even at high temperature, indicating that no phase transition occurs for this chalcogenide-based material. The electrical test results show that the SiGeAsTeN-based devices exhibit good threshold switching characteristics and the switching voltage decreases with the increasing As content. The decrease in valence alternation pairs, reducing trap state density, may be the physical mechanism for lower switch-on voltage, which makes the SiGeAsTeN material more applicable in selector devices through component optimization.

  13. Performance improvement of Ge-Sb-Te material by GaSb doping for phase change memory

    International Nuclear Information System (INIS)

    Lu, Yegang; Zhang, Zhonghua; Song, Sannian; Cheng, Limin; Song, Zhitang; Shen, Xiang; Wang, Guoxiang; Dai, Shixun

    2013-01-01

    Effects of GaSb doping on phase change characteristics of Ge-Sb-Te material are investigated by in situ resistance and x-ray diffraction measurement, optical spectroscopy, and x-ray photoelectron spectroscopy. The crystallization temperature and data retention of Ge-Sb-Te material increase significantly by the addition of GaSb, which results from the high thermal stability of amorphous GaSb. In addition, GaSb-doped Ge-Sb-Te material exhibits faster crystallization speed due to the change in electronic states as a result of the formation of chemical bonds with Ga element. Incorporation of GaSb is highly effective way to enhance the comprehensive performance of Ge-Sb-Te material for phase change memory.

  14. Bipolar Electrode Sample Preparation Devices

    Science.gov (United States)

    Wang, Yi (Inventor); Song, Hongjun (Inventor); Pant, Kapil (Inventor)

    2017-01-01

    An analyte selection device can include: a body defining a fluid channel having a channel inlet and channel outlet; a bipolar electrode (BPE) between the inlet and outlet; one of an anode or cathode electrically coupled with the BPE on a channel inlet side of the BPE and the other of the anode or cathode electrically coupled with the BPE on a channel outlet side of the BPE; and an electronic system operably coupled with the anode and cathode so as to polarize the BPE. The fluid channel can have any shape or dimension. The channel inlet and channel outlet can be longitudinal or lateral with respect to the longitudinal axis of the channel. The BPE can be any metallic member, such as a flat plate on a wall or mesh as a barrier BPE. The anode and cathode can be located at a position that polarizes the BPE.

  15. Composite substrate for bipolar electrodes

    Science.gov (United States)

    Tekkanat, Bora; Bolstad, James J.

    1992-12-22

    Substrates for electrode systems, particularly those to be used for bipolar electrodes in zinc-bromine batteries, are disclosed. The substrates preferably include carbon-black as a conductive filler in a polymeric matrix, with reinforcing materials such as glass fibers. Warpage of the zinc-bromine electrodes which was experienced in the prior art and which was believed to be caused by physical expansion of the electrodes due to bromine absorption by the carbon-black, is substantially eliminated when new substrate fabrication techniques are employed. In the pesent invention, substrates are prepared using a lamination process known as glass mat reinforced thermoplastics technology or, in an alternate embodiment, the substrate is made using a slurry process.

  16. Corrosion resistant amorphous metals and methods of forming corrosion resistant amorphous metals

    Science.gov (United States)

    Farmer, Joseph C [Tracy, CA; Wong, Frank M. G. [Livermore, CA; Haslam, Jeffery J [Livermore, CA; Yang, Nancy [Lafayette, CA; Lavernia, Enrique J [Davis, CA; Blue, Craig A [Knoxville, TN; Graeve, Olivia A [Reno, NV; Bayles, Robert [Annandale, VA; Perepezko, John H [Madison, WI; Kaufman, Larry [Brookline, MA; Schoenung, Julie [Davis, CA; Ajdelsztajn, Leo [Walnut Creek, CA

    2009-11-17

    A system for coating a surface comprises providing a source of amorphous metal, providing ceramic particles, and applying the amorphous metal and the ceramic particles to the surface by a spray. The coating comprises a composite material made of amorphous metal that contains one or more of the following elements in the specified range of composition: yttrium (.gtoreq.1 atomic %), chromium (14 to 18 atomic %), molybdenum (.gtoreq.7 atomic %), tungsten (.gtoreq.1 atomic %), boron (.ltoreq.5 atomic %), or carbon (.gtoreq.4 atomic %).

  17. Phase-change material Ge0.61Sb2Te for application in high-speed phase change random access memory

    Science.gov (United States)

    Gu, Yifeng; Song, Sannian; Song, Zhitang; Bai, Suyuan; Cheng, Yan; Zhang, Zhonghua; Liu, Bo; Feng, Songlin

    2013-03-01

    Compared with Ge2Sb2Te5, Ge0.61Sb2Te has higher crystallization temperature (˜200.5 °C), larger crystallization activation energy (˜3.28 eV), and better data retention (˜120.8 °C for 10 yr). The switching between amorphous and crystalline state could be triggered by the electric pulse of as short as 10 ns. With the resistance ratio of two orders of magnitude, the endurance test was up to 106 cycles. Ge0.61Sb2Te material is a promising candidate for the trade-off between programming speed and data retention.

  18. Strain relaxation during solid-phase epitaxial crystallisation of Ge{sub x}Si{sub 1-x} alloy layers with depth dependent G{sub e} compositions

    Energy Technology Data Exchange (ETDEWEB)

    Wong, Wahchung; Elliman, R.G.; Kringhoj, P. [Australian National Univ., Canberra, ACT (Australia). Research School of Physical Sciences

    1993-12-31

    The solid-phase epitaxial crystallisation of depth dependent Ge{sub x}Si{sub lx} alloy layers produced by implanting Ge into Si substrates was studied. In-situ monitoring was done using time-resolved reflectivity (TRR) whilst post-anneal defect structures were characterised by Rutherford backscattering and channeling spectrometry (RBS-C) and transmission electron microscopy (TEM). Particular attention was directed at Ge concentrations above the critical concentration for the growth of fully strained layers. Strain relief is shown to be correlated with a sudden reduction in crystallisation velocity caused by roughening of the crystalline/amorphous interface. 11 refs., 1 tab., 2 figs.

  19. Electrical and Thermal Conductivity and Conduction Mechanism of Ge2Sb2Te5 Alloy

    Science.gov (United States)

    Lan, Rui; Endo, Rie; Kuwahara, Masashi; Kobayashi, Yoshinao; Susa, Masahiro

    2017-11-01

    Ge2Sb2Te5 alloy has drawn much attention due to its application in phase-change random-access memory and potential as a thermoelectric material. Electrical and thermal conductivity are important material properties in both applications. The aim of this work is to investigate the temperature dependence of the electrical and thermal conductivity of Ge2Sb2Te5 alloy and discuss the thermal conduction mechanism. The electrical resistivity and thermal conductivity of Ge2Sb2Te5 alloy were measured from room temperature to 823 K by four-terminal and hot-strip method, respectively. With increasing temperature, the electrical resistivity increased while the thermal conductivity first decreased up to about 600 K then increased. The electronic component of the thermal conductivity was calculated from the Wiedemann-Franz law using the resistivity results. At room temperature, Ge2Sb2Te5 alloy has large electronic thermal conductivity and low lattice thermal conductivity. Bipolar diffusion contributes more to the thermal conductivity with increasing temperature. The special crystallographic structure of Ge2Sb2Te5 alloy accounts for the thermal conduction mechanism.

  20. Bipolar disorder and neurophysiologic mechanisms

    Directory of Open Access Journals (Sweden)

    Simon M McCrea

    2008-11-01

    Full Text Available Simon M McCreaDepartments of Neurology and Neuroophthalmology, University of British Columbia, 2550 Willow Street, Vancouver, British Columbia, Canada V5Z 3N9Abstract: Recent studies have suggested that some variants of bipolar disorder (BD may be due to hyperconnectivity between orbitofrontal (OFC and temporal pole (TP structures in the dominant hemisphere. Some initial MRI studies noticed that there were corpus callosum abnormalities within specific regional areas and it was hypothesized that developmentally this could result in functional or effective connectivity changes within the orbitofrontal-basal ganglia-thalamocortical circuits. Recent diffusion tensor imaging (DTI white matter fiber tractography studies may well be superior to region of interest (ROI DTI in understanding BD. A “ventral semantic stream” has been discovered connecting the TP and OFC through the uncinate and inferior longitudinal fasciculi and the elusive TP is known to be involved in theory of mind and complex narrative understanding tasks. The OFC is involved in abstract valuation in goal and sub-goal structures and the TP may be critical in binding semantic memory with person–emotion linkages associated with narrative. BD patients have relative attenuation of performance on visuoconstructional praxis consistent with an atypical localization of cognitive functions. Multiple lines of evidence suggest that some BD alleles are being selected for which could explain the enhanced creativity in higher-ability probands. Associations between ROI’s that are not normally connected could explain the higher incidence of artistic aptitude, writing ability, and scientific achievements among some mood disorder subjects.Keywords: bipolar disorder, diffusion tensor imaging, white matter tractography, inferior longitudinal fasciculus, inferior fronto-occipital fasciculus, uncinate fasciculus, mood dysphoria, creativity, ventral semantic stream, writing ability, artistic aptitude

  1. Surface magnetic structures in amorphous ferromagnetic microwires

    International Nuclear Information System (INIS)

    Usov, N.A.; Serebryakova, O.N.; Gudoshnikov, S.A.; Tarasov, V.P.

    2017-01-01

    The spatial period of magnetization perturbations that occur near the surface of magnetic nanotube or nanowire under the influence of surface magnetic anisotropy is determined by means of numerical simulation as a function of the sample geometry and material parameters. The surface magnetization distribution obtained is then used to estimate the period of the surface magnetic texture in amorphous microwire of several micrometers in diameter by means of appropriate variational procedure. The period of the surface magnetic texture in amorphous microwire is found to be significantly smaller than the wire diameter. - Highlights: • Magnetic structure may arise near the magnetic nanotube surface under the influence of surface magnetic anisotropy. • The period of the surface magnetization pattern is calculated as a function of the sample geometry. • Similar magnetic structure may exist in amorphous microwire of several micrometers in diameter. • The period of the surface magnetic structure in amorphous wire is found to be significantly smaller than the wire diameter.

  2. Bulk amorphous Mg-based alloys

    DEFF Research Database (Denmark)

    Pryds, Nini

    2004-01-01

    The present paper describes the preparation and properties of bulk amorphous quarternary Mg-based alloys and the influence of additional elements on the ability of the alloy to form bulk amorphous. The main goal is to find a Mg-based alloy system which shows both high strength to weight ratio...... and a low glass transition temperature. The alloys were prepared by using a relatively simple technique, i.e. rapid cooling of the melt in a copper wedge mould. The essential structural changes that are achieved by going from the amorphous to the crystalline state through the supercooled liquid state...... are discussed in this paper. On the basis of these measurements phase diagrams of the different systems were constructed. Finally, it is demonstrated that when pressing the bulk amorphous alloy onto a metallic dies at temperatures within the supercooled liquid region, the alloy faithfully replicates the surface...

  3. Theoretical Considerations in Developing Amorphous Solid Dispersions

    DEFF Research Database (Denmark)

    Laitinen, Riikka; Priemel, Petra Alexandra; Surwase, Sachin

    2014-01-01

    to their glass-forming ability and glass stability. In the main parts of this chapter, we review theoretical approaches to determine amorphous drug polymer miscibility and crystalline drug polymer solubility, as a prerequisite to develop amorphous solid dispersions (glass solutions).......Before pursuing the laborious route of amorphous solid dispersion formulation and development, which is the topic of many of the subsequent chapters in this book, the formulation scientist would benefit from a priori knowledge whether the amorphous route is a viable one for a given drug and how...... much solubility improvement, and hence increase in bioavailability, can be expected, and what forms of solid dispersion have been developed in the past. In this chapter, we therefore initially define the various forms of solid dispersions, and then go on to discuss properties of pure drugs with respect...

  4. Surface magnetic structures in amorphous ferromagnetic microwires

    Energy Technology Data Exchange (ETDEWEB)

    Usov, N.A., E-mail: usov@obninsk.ru [National University of Science and Technology «MISIS», 119049 Moscow (Russian Federation); Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation, Russian Academy of Sciences, IZMIRAN, 108840 Troitsk, Moscow (Russian Federation); Serebryakova, O.N.; Gudoshnikov, S.A. [National University of Science and Technology «MISIS», 119049 Moscow (Russian Federation); Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation, Russian Academy of Sciences, IZMIRAN, 108840 Troitsk, Moscow (Russian Federation); Tarasov, V.P. [National University of Science and Technology «MISIS», 119049 Moscow (Russian Federation)

    2017-05-01

    The spatial period of magnetization perturbations that occur near the surface of magnetic nanotube or nanowire under the influence of surface magnetic anisotropy is determined by means of numerical simulation as a function of the sample geometry and material parameters. The surface magnetization distribution obtained is then used to estimate the period of the surface magnetic texture in amorphous microwire of several micrometers in diameter by means of appropriate variational procedure. The period of the surface magnetic texture in amorphous microwire is found to be significantly smaller than the wire diameter. - Highlights: • Magnetic structure may arise near the magnetic nanotube surface under the influence of surface magnetic anisotropy. • The period of the surface magnetization pattern is calculated as a function of the sample geometry. • Similar magnetic structure may exist in amorphous microwire of several micrometers in diameter. • The period of the surface magnetic structure in amorphous wire is found to be significantly smaller than the wire diameter.

  5. Climatic factors and bipolar affective disorder

    DEFF Research Database (Denmark)

    Christensen, Ellen Margrethe; Larsen, Jens Knud; Gjerris, Annette

    2008-01-01

    In bipolar disorder, the factors provoking a new episode are unknown. As a seasonal variation has been noticed, it has been suggested that weather conditions may play a role. The aim of the study was to elucidate whether meteorological parameters influence the development of new bipolar phases....... A group of patients with at least three previous hospitalizations for bipolar disorder was examined every 3 months for up to 3 years. At each examination an evaluation of the affective phase was made according to the Hamilton Depression Scale (HAM-D(17)), and the Bech-Rafaelsen Mania Rating Scale (MAS......). In the same period, daily recordings from the Danish Meteorological Institute were received. We found no correlations between onset of bipolar episodes [defined as MAS score of 11 or more (mania) and as HAM-D(17) score of 12 or more (depression)] and any meteorological parameters. We found a statistical...

  6. Gene environment interactions in bipolar disorder.

    Science.gov (United States)

    Pregelj, Peter

    2011-09-01

    It has been estimated that the heritable component of bipolar disorder ranges between 80 and 90%. However, even genome-wide association studies explain only a fraction of phenotypic variability not resolving the problem of "lost heritability". Although direct evidence for epigenetic dysfunction in bipolar disorder is still limited, methodological technologies in epigenomic profiling have advanced, offering even single cell analysing and resolving the problem of cell heterogeneity in epigenetics research. Gene overlapping with other mental disorders represents another problem in identifying potential susceptibility genes in bipolar disorder. Better understanding of the interplay between multiple environmental and genetic factors involved in the patogenesis of bipolar disorder could provide relevant information for treatment of patients with this complex disorder. Future studies on the role of these factors in psychopathological conditions, subphenotypes and endophenotypes may greatly benefit by using more precise clinical data and a combined approach with multiple research tools incorporated into a single study.

  7. Are rates of pediatric bipolar disorder increasing?

    DEFF Research Database (Denmark)

    Kessing, Lars Vedel; Vradi, Eleni; Andersen, Per Kragh

    2014-01-01

    Studies from the USA suggest that rates of pediatric bipolar disorder have increased since the mid-90s, but no study outside the USA has been published on the rates of pediatric bipolar disorder. Further, it is unclear whether an increase in rates reflects a true increase in the illness or more...... diagnostic attention. Using nationwide registers of all inpatients and outpatients contacts to all psychiatric hospitals in Denmark, we investigated (1) gender-specific rates of incident pediatric mania/bipolar disorder during a period from 1995 to 2012, (2) whether age and other characteristics...... for pediatric mania/bipolar disorder changed during the calendar period (1995 to 2003 versus 2004 to 2012), and (3) whether the diagnosis is more often made at first psychiatric contact in recent time compared to earlier according to gender. Totally, 346 patients got a main diagnosis of a manic episode (F30...

  8. Internet use by patients with bipolar disorder

    DEFF Research Database (Denmark)

    Bauer, Rita; Conell, Jörn; Glenn, Tasha

    2016-01-01

    There is considerable international interest in online education of patients with bipolar disorder, yet little understanding of how patients use the Internet and other sources to seek information. 1171 patients with a diagnosis of bipolar disorder in 17 countries completed a paper-based, anonymous...... survey. 81% of the patients used the Internet, a percentage similar to the general public. Older age, less education, and challenges in country telecommunications infrastructure and demographics decreased the odds of using the Internet. About 78% of the Internet users looked online for information...... for information on bipolar disorder consulted medical professionals plus a mean of 2.3 other information sources such as books, physician handouts, and others with bipolar disorder. Patients not using the Internet consulted medical professionals plus a mean of 1.6 other information sources. The percentage...

  9. Amorphous Phases on the Surface of Mars

    Science.gov (United States)

    Rampe, E. B.; Morris, R. V.; Ruff, S. W.; Horgan, B.; Dehouck, E.; Achilles, C. N.; Ming, D. W.; Bish, D. L.; Chipera, S. J.

    2014-01-01

    Both primary (volcanic/impact glasses) and secondary (opal/silica, allophane, hisingerite, npOx, S-bearing) amorphous phases appear to be major components of martian surface materials based on orbital and in-situ measurements. A key observation is that whereas regional/global scale amorphous components include altered glass and npOx, local scale amorphous phases include hydrated silica/opal. This suggests widespread alteration at low water-to-rock ratios, perhaps due to snow/ice melt with variable pH, and localized alteration at high water-to-rock ratios. Orbital and in-situ measurements of the regional/global amorphous component on Mars suggests that it is made up of at least three phases: npOx, amorphous silicate (likely altered glass), and an amorphous S-bearing phase. Fundamental questions regarding the composition and the formation of the regional/global amorphous component(s) still remain: Do the phases form locally or have they been homogenized through aeolian activity and derived from the global dust? Is the parent glass volcanic, impact, or both? Are the phases separate or intimately mixed (e.g., as in palagonite)? When did the amorphous phases form? To address the question of source (local and/or global), we need to look for variations in the different phases within the amorphous component through continued modeling of the chemical composition of the amorphous phases in samples from Gale using CheMin and APXS data. If we find variations (e.g., a lack of or enrichment in amorphous silicate in some samples), this may imply a local source for some phases. Furthermore, the chemical composition of the weathering products may give insight into the formation mechanisms of the parent glass (e.g., impact glasses contain higher Al and lower Si [30], so we might expect allophane as a weathering product of impact glass). To address the question of whether these phases are separate or intimately mixed, we need to do laboratory studies of naturally altered samples made

  10. Amorphous Carbon-Boron Nitride Nanotube Hybrids

    Science.gov (United States)

    Kim, Jae Woo (Inventor); Siochi, Emilie J. (Inventor); Wise, Kristopher E. (Inventor); Lin, Yi (Inventor); Connell, John (Inventor)

    2016-01-01

    A method for joining or repairing boron nitride nanotubes (BNNTs). In joining BNNTs, the nanotube structure is modified with amorphous carbon deposited by controlled electron beam irradiation to form well bonded hybrid a-C/BNNT structures. In repairing BNNTs, the damaged site of the nanotube structure is modified with amorphous carbon deposited by controlled electron beam irradiation to form well bonded hybrid a-C/BNNT structures at the damage site.

  11. Amorphization Mechanism of Icosahedral Platinum Clusters

    International Nuclear Information System (INIS)

    Apra, Edoardo; Baletto, Francesca; Ferrando, Riccardo; Fortunelli, Alessandro

    2004-01-01

    The amorphization mechanism of high-symmetry pt nanoclusters is investigated by a combination of Molecular Dynamics simulations and Density Functional calculations. A general mechanism for amorphization, involving rosette-like structural transformations at fivefold vertices, is proposed. IN the tosette, a fivefold vertex is transformed into a hexagonal ring. We show that for icosahedral Pt nanoclusters, this transformation is associated with an energy gain, so that their most favorable structures have a low symmetry even at icosahedral magic numbers

  12. A Magnetic Sensor with Amorphous Wire

    Directory of Open Access Journals (Sweden)

    Dongfeng He

    2014-06-01

    Full Text Available Using a FeCoSiB amorphous wire and a coil wrapped around it, we have developed a sensitive magnetic sensor. When a 5 mm long amorphous wire with the diameter of 0.1 mm was used, the magnetic field noise spectrum of the sensor was about 30 pT/ÖHz above 30 Hz. To show the sensitivity and the spatial resolution, the magnetic field of a thousand Japanese yen was scanned with the magnetic sensor.

  13. Thyroid Functions and Bipolar Affective Disorder

    OpenAIRE

    Chakrabarti, Subho

    2011-01-01

    Accumulating evidence suggests that hypothalamo-pituitary-thyroid (HPT) axis dysfunction is relevant to the pathophysiology and clinical course of bipolar affective disorder. Hypothyroidism, either overt or more commonly subclinical, appears to the commonest abnormality found in bipolar disorder. The prevalence of thyroid dysfunction is also likely to be greater among patients with rapid cycling and other refractory forms of the disorder. Lithium-treatment has potent antithyroid effects and c...

  14. Biological dysrhythm in remitted bipolar I disorder.

    Science.gov (United States)

    Iyer, Aishwarya; Palaniappan, Pradeep

    2017-12-01

    Recent treatment guidelines support treatment of biological rhythm abnormalities as a part of treatment of bipolar disorder, but still, literature examining various domains (Sleep, Activity, Social, and Eating) of biological rhythm and its clinical predictors are less. The main aim of our study is to compare various domains of biological rhythm among remitted bipolar I subjects and healthy controls. We also explored for any association between clinical variables and biological rhythm among bipolar subjects. 40 subjects with Bipolar I disorder and 40 healthy controls who met inclusion and exclusion criteria were recruited for the study. Diagnoses were ascertained by a qualified psychiatrist using MINI 5.0. Sociodemographic details, biological rhythm (BRIAN-Biological Rhythm Interview of assessment in Neuropsychiatry) and Sleep functioning (PSQI- Pittsburgh Sleep Quality Index) were assessed in all subjects. Mean age of the Bipolar subjects and controls were 41.25±11.84years and 38.25±11.25 years respectively. Bipolar subjects experienced more biological rhythm disturbance when compared to healthy controls (total BRIAN score being 34.25±9.36 vs 28.2±6.53) (p=0.002). Subsyndromal depressive symptoms (HDRS) had significant positive correlation with BRIAN global scores(r=0.368, p=0.02). Linear regression analysis showed that number of episodes which required hospitalization (β=0.601, t=3.106, P=0.004), PSQI (β=0.394, t=2.609, p=0.014), HDRS (β=0.376, t=2.34, t=0.036) explained 31% of variance in BRIAN scores in remitted bipolar subjects. Biological rhythm disturbances seem to persist even after clinical remission of bipolar illness. More studies to look into the impact of subsyndromal depressive symptoms on biological rhythm are needed. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Bipolar transistor in VESTIC technology: prototype

    Science.gov (United States)

    Mierzwiński, Piotr; Kuźmicz, Wiesław; Domański, Krzysztof; Tomaszewski, Daniel; Głuszko, Grzegorz

    2016-12-01

    VESTIC technology is an alternative for traditional CMOS technology. This paper presents first measurement data of prototypes of VES-BJT: bipolar transistors in VESTIC technology. The VES-BJT is a bipolar transistor on the SOI substrate with symmetric lateral structure and both emitter and collector made of polysilicon. The results indicate that VES-BJT can be a device with useful characteristics. Therefore, VESTIC technology has the potential to become a new BiCMOS-type technology with some unique properties.

  16. Transtorno afetivo bipolar: um enfoque transcultural

    OpenAIRE

    Sanches,Marsal; Jorge,Miguel Roberto

    2004-01-01

    Considerando-se que existem diferenças importantes na maneira como as emoções são vivenciadas e expressas em diferentes culturas, a apresentação e o manejo do transtorno afetivo bipolar sofrem influência de fatores culturais. O presente artigo realiza uma breve revisão da evidência referente aos aspectos transculturais do transtorno bipolar.

  17. O transtorno bipolar na mulher Bipolar disorder in women

    Directory of Open Access Journals (Sweden)

    Alexandro de Borja Gonçalves Guerra

    2005-01-01

    Full Text Available Diferenças sexuais, descritas em vários transtornos psiquiátricos, também parecem estar presentes no transtorno afetivo bipolar (TAB. A prevalência do TAB tipo I se distribui igualmente entre mulheres e homens. Mulheres parecem estar sujeitas a um risco maior de ciclagem rápida e mania mista, condições que fariam do TAB um transtorno com curso mais prejudicial no sexo feminino. Uma diátese depressiva mais marcante, uso excessivo de antidepressivos e diferenças hormonais surgem como hipóteses para explicar essas diferenças fenomenológicas, apesar das quais, mulheres e homens parecem responder igualmente ao tratamento medicamentoso. A indicação de anticonvulsivantes como primeira escolha em mulheres é controversa, a não ser para o tratamento da mania mista e, talvez, da ciclagem rápida. O tratamento do TAB na gravidez deve levar em conta tanto os riscos de exposição aos medicamentos quanto à doença materna. A profilaxia do TAB no puerpério está fortemente indicada em decorrência do grande risco de recorrência da doença nesse período. Embora, de modo geral, as medicações psicotrópicas estejam contra-indicadas durante a amamentação, entre os estabilizadores do humor, a carbamazepina e o valproato são mais seguros do que o lítio. Mais estudos são necessários para a confirmação das diferenças de curso do TAB entre mulheres e homens e a investigação de possíveis diferenças na efetividade dos tratamentos.Gender differences, described in several psychiatric disorders, seem to be also present in bipolar disorder (BD. The prevalence of bipolar I disorder is equally distributed between women and men. Women seem to be at higher risk for rapid cycling and mixed mania, conditions that could make BD a disorder with a more severe course in the female sex. A marked depressive diathesis among women, greatest use of antidepressants and hormonal differences have been mentioned as hypotheses to explain these

  18. Comorbidity bipolar disorder and personality disorders.

    Science.gov (United States)

    Latalova, Klara; Prasko, Jan; Kamaradova, Dana; Sedlackova, Jana; Ociskova, Marie

    2013-01-01

    Outcome in bipolar patients can be affected by comorbidity of other psychiatric disorders. Comorbid personality disorders are frequent and may complicate the course of bipolar illness. We have much information about treating patients with uncomplicated bipolar disorder (BD) but much less knowledge about possibilities for patients with the comorbidity of BD and personality disorder. We conducted a series of literature searches using, as key words or as items in indexed fields, bipolar disorder and personality disorder or personality traits. Articles were obtained by searching MEDLINE from 1970 to 2012. In addition, we used other papers cited in articles from these searches, or cited in articles used in our own work. Tests of personality traits indicated that euthymic bipolar patients have higher scores on harm avoidance, reward dependence, and novelty seeking than controls. Elevation of novelty seeking in bipolar patients is associated with substance abuse comorbidity. Comorbidity with personality disorders in BD patients is associated with a more difficult course of illness (such as longer episodes, shorter time euthymic, and earlier age at onset) and an increase in comorbid substance abuse, suicidality and aggression. These problems are particularly pronounced in comorbidity with borderline personality disorder. Comorbidity with antisocial personality disorder elicits a similar spectrum of difficulties; some of the antisocial behavior exhibited by patients with this comorbidity is mediated by increased impulsivity.

  19. Sexual health and women with bipolar disorder.

    Science.gov (United States)

    McCandless, Fiona; Sladen, Claire

    2003-10-01

    The aim of this paper is to illustrate the importance of sexual health promotion strategies for women with bipolar disorder in order to stimulate interest and debate in this area of care. Sexual health promotion is an important aspect of holistic nursing care. However, the literature indicates that nurses are reluctant to discuss sexual health and sexual behaviour with their clients. People with bipolar disorder warrant special consideration with regards to sexual health because the nature of the manic, or hypomanic, mood state is associated in some cases with sexually risky behaviour. For women with bipolar disorder, the associated risks include the threat of unplanned pregnancy or sexually transmitted diseases. To ignore sexual health and sexual behaviour in mental health care increases the vulnerability of women who may already be at risk of sexual exploitation. CASE EXAMPLE: A brief case example is included to demonstrate how the sexual health of a young woman with bipolar disorder was promoted. The sexual health promotion that was incorporated into her care enabled her to make a choice about appropriate contraception, and also provided her with the opportunity to explore acceptable boundaries in different types of interpersonal relationships. As a result of the episodic nature of Bipolar disorder, it is impossible to state whether the positive outcomes from this strategy will be enduring or not. Consideration of sexual health is an essential element of the care of women with Bipolar disorder. To ignore it is to neglect an important sphere of human behaviour that can be affected by the condition.

  20. The role of sleep in bipolar disorder

    Directory of Open Access Journals (Sweden)

    Gold AK

    2016-06-01

    Full Text Available Alexandra K Gold,1 Louisa G Sylvia,1,2 1Department of Psychiatry, Massachusetts General Hospital, 2Harvard Medical School, Boston, MA, USA Abstract: Bipolar disorder is a serious mental illness characterized by alternating periods of elevated and depressed mood. Sleep disturbances in bipolar disorder are present during all stages of the condition and exert a negative impact on overall course, quality of life, and treatment outcomes. We examine the partnership between circadian system (process C functioning and sleep–wake homeostasis (process S on optimal sleep functioning and explore the role of disruptions in both systems on sleep disturbances in bipolar disorder. A convergence of evidence suggests that sleep problems in bipolar disorder result from dysregulation across both process C and process S systems. Biomarkers of depressive episodes include heightened fragmentation of rapid eye movement (REM sleep, reduced REM latency, increased REM density, and a greater percentage of awakenings, while biomarkers of manic episodes include reduced REM latency, greater percentage of stage I sleep, increased REM density, discontinuous sleep patterns, shortened total sleep time, and a greater time awake in bed. These findings highlight the importance of targeting novel treatments for sleep disturbance in bipolar disorder. Keywords: bipolar disorder, circadian rhythms, sleep–wake homeostasis

  1. Classification of cognitive performance in bipolar disorder.

    Science.gov (United States)

    Sparding, Timea; Silander, Katja; Pålsson, Erik; Östlind, Josefin; Ekman, Carl Johan; Sellgren, Carl M; Joas, Erik; Hansen, Stefan; Landén, Mikael

    2017-09-01

    To understand the etiology of cognitive impairment associated with bipolar disorder, we need to clarify potential heterogeneity in cognitive functioning. To this end, we used multivariate techniques to study if the correlation structure of cognitive abilities differs between persons with bipolar disorder and controls. Clinically stable patients with bipolar disorder (type I: n = 64; type II: n = 44) and healthy controls (n = 86) were assessed with a wide range of cognitive tests measuring executive function, speed, memory, and verbal skills. Data were analysed with multivariate techniques. A distinct subgroup (∼30%) could be identified that performed significantly poorer on tests concerning memory function. This cognitive phenotype subgroup did not differ from the majority of bipolar disorder patients with respect to other demographic or clinical characteristics. Whereas the majority of patients performed similar to controls, a subgroup of patients with bipolar disorder differed substantially from healthy controls in the correlation pattern of low-level cognitive abilities. This suggests that cognitive impairment is not a general trait in bipolar disorder but characteristic of a cognitive subgroup. This has important clinical implications for cognitive rehabilitation and remediation.

  2. Early maladaptive schemas in bipolar disorder.

    Science.gov (United States)

    Ak, Mehmet; Lapsekili, Nergis; Haciomeroglu, Bikem; Sutcigil, Levent; Turkcapar, Hakan

    2012-09-01

    According to the cognitive model of depression, negative schemas, formed in early life, increase susceptibility to depression. The objective of this study was to investigate schemas that are proposed to increase susceptibility of depression in bipolar disorder patients who have had depressive episodes. Eighteen patients diagnosed with bipolar disorder according to DSM-IV and a healthy control group (N= 20) constituted the sample of the study. The Beck Depression Inventory, Young Mania Rating Scale, and Young Schema Scale were applied to patients in order to determine the level of symptoms and schemas. When the scores obtained from Young Schema Scale were compared between groups, significant differences were observed between bipolar patients and control group on all the schemas except abandonment, emotional deprivation, defectiveness, vulnerability to harm or illness, and approval seeking. The negative schema scores of bipolar patients were significantly higher than those of the control group. Of all schemas included in the Young Schema Scale, the scores of bipolar group were higher than the scores of the control group. These findings suggest that, in cognitive-based psychotherapeutic approaches for patients with bipolar disorder, it would be more effective to focus on schemas related to the perception and allowance of feelings at the proper time and the instability of self-perceptions. © 2011 The British Psychological Society.

  3. Preparation of bipolar membranes by electrospinning

    International Nuclear Information System (INIS)

    Pan, Jiefeng; Hou, Linxiao; Wang, Qiuyue; He, Yubin; Wu, Liang; Mondal, Abhishek N.; Xu, Tongwen

    2017-01-01

    A new preparative pathway for the bipolar membranes was initiated via the electrospinning and hot-press process. The prepared bipolar membrane was consisting of sulfonated poly (phenylene oxide), polyethylene glycol, and quaternized poly (phenylene oxide). The above mentioned membrane was fabricated by the continuous electrospinning of the respective layer, followed by the solvent atmosphere treatment and hot-pressing, to obtain a transparent and dense structure. The thickness of each layer can be easily tuned by controlling the electrospinning parameters. The clear interfacial structure was observed and confirmed by the scanning electron microscope. The bipolar performance is evaluated by the current–voltage curves and production yield of acid and base. The final optimized bipolar membrane had similar yield of acid and base as the casting membrane. However, extremely lower potential drop value was observed when they are applied for the production of acid and base. The experimental results showed that, electrospinning is an effective and well controlled way to fabricate bipolar membranes, in which anion or cation exchange layer as well as interfacial layer can be easily changed or added as requested. - Highlights: • Bipolar membranes were prepared through electrospinning followed by post-treatment. • As-prepared membranes were successfully applied in electrodialysis for production of acid and base. • Electrospun membranes exhibit better performance than the casting ones.

  4. Preparation of bipolar membranes by electrospinning

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Jiefeng; Hou, Linxiao; Wang, Qiuyue; He, Yubin; Wu, Liang; Mondal, Abhishek N.; Xu, Tongwen, E-mail: twxu@ustc.edu.cn

    2017-01-15

    A new preparative pathway for the bipolar membranes was initiated via the electrospinning and hot-press process. The prepared bipolar membrane was consisting of sulfonated poly (phenylene oxide), polyethylene glycol, and quaternized poly (phenylene oxide). The above mentioned membrane was fabricated by the continuous electrospinning of the respective layer, followed by the solvent atmosphere treatment and hot-pressing, to obtain a transparent and dense structure. The thickness of each layer can be easily tuned by controlling the electrospinning parameters. The clear interfacial structure was observed and confirmed by the scanning electron microscope. The bipolar performance is evaluated by the current–voltage curves and production yield of acid and base. The final optimized bipolar membrane had similar yield of acid and base as the casting membrane. However, extremely lower potential drop value was observed when they are applied for the production of acid and base. The experimental results showed that, electrospinning is an effective and well controlled way to fabricate bipolar membranes, in which anion or cation exchange layer as well as interfacial layer can be easily changed or added as requested. - Highlights: • Bipolar membranes were prepared through electrospinning followed by post-treatment. • As-prepared membranes were successfully applied in electrodialysis for production of acid and base. • Electrospun membranes exhibit better performance than the casting ones.

  5. Tailoring the optical properties of amorphous heavily Er3+-doped Ge-Ga-S thin films

    Czech Academy of Sciences Publication Activity Database

    Reddy, N.K.; Devika, M.; Prashantha, M.; Rames, K.; Ivanova, Z.G.; Zavadil, Jiří

    2013-01-01

    Roč. 15, 3-4 (2013), s. 182-186 ISSN 1454-4164 R&D Projects: GA ČR GAP106/12/2384 Institutional support: RVO:67985882 Keywords : Chalcogenide thin films * Optical properties * Photoinduced changes Subject RIV: JA - Electronics ; Optoelectronics , Electrical Engineering Impact factor: 0.563, year: 2013

  6. Low-frequency noise behavior of polysilicon emitter bipolar junction transistors: a review

    Science.gov (United States)

    Deen, M. Jamal; Pascal, Fabien

    2003-05-01

    For many analog integrated circuit applications, the polysilicon emitter bipolar junction transistor (PE-BJT) is still the preferred choice because of its higher operational frequency and lower noise performance characteristics compared to MOS transistors of similar active areas and at similar biasing currents. In this paper, we begin by motivating the reader with reasons why bipolar transistors are still of great interest for analog integrated circuits. This motivation includes a comparison between BJT and the MOSFET using a simple small-signal equivalent circuit to derive important parameters that can be used to compare these two technologies. An extensive review of the popular theories used to explain low frequency noise results is presented. However, in almost all instances, these theories have not been fully tested. The effects of different processing technologies and conditions on the noise performance of PE-BJTs is reviewed and a summary of some of the key technological steps and device parameters and their effects on noise is discussed. The effects of temperature and emitter geometries scaling is reviewed. It is shown that dispersion of the low frequency noise in ultra-small geometries is a serious issue since the rate of increase of the noise dispersion is faster than the noise itself as the emitter geometry is scaled to smaller values. Finally, some ideas for future research on PE-BJTs, some of which are also applicable to SiGe heteorjunction bipolar transistors and MOSFETs, are presented after the conclusions.

  7. SiGe HBT low noise amplifiers for ultra-wideband systems

    Directory of Open Access Journals (Sweden)

    Popov V. P.

    2013-02-01

    Full Text Available This paper presents the principles of design of integrated circuits low-noise amplifiers (LNA based on silicon-germanium heterojunction bipolar transistors (SiGe HBT for ultra-wideband (UWB systems. UWB systems range 0,5—10,6 GHz are used in communications, radars of medical applications and safety systems. The proposed UWB LNA implemented by inductorless or minimum number of inductors schemes. In this paper researched and designed two variants of UWB LNA 0,5—11 GHz frequency range.

  8. Technology computer aided design for Si, SiGe and GaAs integrated circuits

    CERN Document Server

    Armstrong, GA

    2007-01-01

    The first book to deal with a broad spectrum of process and device design, and modelling issues related to semiconductor devices, bridging the gap between device modelling and process design using TCAD. Examples for types of Si-, SiGe-, GaAs- and InP-based heterostructure MOS and bipolar transistors are compared with experimental data from state-of-the-art devices. With various aspects of silicon heterostructures, this book presents a comprehensive perspective of emerging fields and covers topics ranging from materials to fabrication, devices, modelling and applications. Aimed at research-and-

  9. Fabrication of multilayered Ge nanocrystals embedded in SiOxGeNy films

    International Nuclear Information System (INIS)

    Gao Fei; Green, Martin A.; Conibeer, Gavin; Cho, Eun-Chel; Huang Yidan; Perez-Wurfl, Ivan; Flynn, Chris

    2008-01-01

    Multilayered Ge nanocrystals embedded in SiO x GeN y films have been fabricated on Si substrate by a (Ge + SiO 2 )/SiO x GeN y superlattice approach, using a rf magnetron sputtering technique with a Ge + SiO 2 composite target and subsequent thermal annealing in N 2 ambient at 750 deg. C for 30 min. X-ray diffraction (XRD) measurement indicated the formation of Ge nanocrystals with an average size estimated to be 5.4 nm. Raman scattering spectra showed a peak of the Ge-Ge vibrational mode downward shifted to 299.4 cm -1 , which was caused by quantum confinement of phonons in the Ge nanocrystals. Transmission electron microscopy (TEM) revealed that Ge nanocrystals were confined in (Ge + SiO 2 ) layers. This superlattice approach significantly improved both the size uniformity of Ge nanocrystals and their uniformity of spacing on the 'Z' growth direction

  10. Tratamento da depressão bipolar The treatment of bipolar depression

    Directory of Open Access Journals (Sweden)

    Beny Lafer

    2005-01-01

    Full Text Available O tratamento da depressão bipolar tem sido tema de debate. O uso de antidepressivos, principalmente tricíclicos, nestes pacientes está associado a piores desfechos clínicos. Estudos apontam para uma eficácia limitada de estabilizadores tradicionais como lítio, valproato e carbamazepina no tratamento da depressão bipolar. Em casos de depressão mais grave, há indicativos de que os antidepressivos podem ser úteis, sendo recomendado o uso concomitante de um estabilizador do humor. Novos agentes como a lamotrigina têm sido propostos como efetivos no tratamento da depressão bipolar. Estudos recentes utilizando lamotrigina sugerem a sua eficácia e seguraça no tratamento da depressão bipolar.The treatment of bipolar depression has been an area of debate. The use of antidepressants, particularly the triciclics, has been associated with worse clinical outcomes. Evidence points to a limited efficacy of traditional mood stabilizers such as lithium, valproate and carbamazepine in the treatment of bipolar depression. In cases where depression is more severe, there is evidence that antidepressants may be useful. The use of antidepressants should be in association with a mood stabilizer. New agents such as lamotrigine have been put forward as effective in the treatment of bipolar depression. Recent studies using lamotrigine suggest its efficacy and safety in the treatment of bipolar depression.

  11. Clinical, Demographic, and Familial Correlates of Bipolar Spectrum Disorders among Offspring of Parents with Bipolar Disorder

    Science.gov (United States)

    Goldstein, Benjamin I.; Shamseddeen, Wael; Axelson, David A.; Kalas, Cathy; Monk, Kelly; Brent, David A.; Kupfer, David J.; Birmaher, Boris

    2010-01-01

    Objective: Despite increased risk, most offspring of parents with bipolar disorder (BP) do not manifest BP. The identification of risk factors for BP among offspring could improve preventive and treatment strategies. We examined this topic in the Pittsburgh Bipolar Offspring Study (BIOS). Method: Subjects included 388 offspring, ages 7-17 years,…

  12. Terapia comportamental cognitiva para pessoas com transtorno bipolar Cognitive behavioral therapy for bipolar disorders

    Directory of Open Access Journals (Sweden)

    Francisco Lotufo Neto

    2004-10-01

    Full Text Available Descrição dos objetivos e principais técnicas da terapia comportamental cognitiva usadas para a psicoterapia das pessoas com transtorno bipolar.Objectives and main techniques of cognitive behavior therapy for the treatment of bipolar disorder patients are described.

  13. Raman scattering on a series of phase-change material (GeTe,Sb{sub 2}Te{sub 3},Ge{sub 15}Sb{sub 85}, and Ge{sub x}Sb{sub y}Te{sub z})

    Energy Technology Data Exchange (ETDEWEB)

    Hinterberg, Judith; Rueckamp, Reinhard; Guentherodt, Gernot [2. Physikalisches Institut, RWTH Aachen (Germany); Woda, Michael; Wuttig, Matthias [1. Physikalisches Institut, RWTH Aachen (Germany); Grueninger, Markus [2. Physikalisches Institut, Universitaet Koeln (Germany)

    2008-07-01

    The phase-change material Ge{sub x}Sb{sub y}Te{sub z} (GST) are widely used for optical data storage, but also their potential for so-called phase-change (PC)-RAMs is promising. However, their local structure - in particular in the amorphous phase - and the ion displacements across the phase transition are not well understood. In order to reveal the local structure we investigate the phonon spectra of various compounds of the pseudo-binary line from Sb{sub 2}Te{sub 3} to GeTe as a function of temperature by means of Raman spectroscopy. In particular, we compare Raman spectra of the amorphous, the metastable, and the stable phases of GST124, GST224, GST214, GST225, GeTe, Sb{sub 2}Te{sub 3}, and Ge{sub 15}Sb{sub 85}. Near the phase transition, we find a remarkable similarity between GST and Sb{sub 2}Te{sub 3}. In contrast to recent claims in the literature, the ordering process in GST is not only dominated by the Ge atoms.

  14. Atomic-scale structure of the glassy Ge2Sb2Te5 phase change material: A quantitative assessment via first-principles molecular dynamics

    Science.gov (United States)

    Bouzid, Assil; Ori, Guido; Boero, Mauro; Lampin, Evelyne; Massobrio, Carlo

    2017-12-01

    The amorphous structure of the phase change material Ge2Sb2Te5 (GST) has been the object of controversial structural models. By employing first-principles molecular dynamics within density functional theory, we are able to obtain quantitative agreement with experimental structural findings for the topology of glassy GST. To this end, we take full advantage of a thoughtful, well established choice of the exchange-correlation (XC) functional (Becke-Lee-Yang-Parr, BLYP), combined with appropriate options for the nonlocal part in the pseudopotential construction for Ge. Results obtained by using the Perdew-Burke-Ernzerhof (PBE) XC functional and a similar strategy for the Ge pseudopotential constructions are also presented, since they are very valuable and worthy of consideration. The atomic structure of glassy GST is characterized by Ge atoms lying in a predominant tetrahedral network, albeit a non-negligible fraction of Ge atoms are also found in defective octahedra.

  15. [Circadian markers and genes in bipolar disorder].

    Science.gov (United States)

    Yeim, S; Boudebesse, C; Etain, B; Belliviera, F

    2015-09-01

    Bipolar disorder is a severe and complex multifactorial disease, characterized by alternance of acute episodes of depression and mania/hypomania, interspaced by euthymic periods. The etiological determinants of bipolar disorder yet, are still poorly understood. For the last 30 years, chronobiology is an important field of investigation to better understand the pathophysiology of bipolar disorder. We conducted a review using Medline, ISI Database, EMBase, PsyInfo up to January 2015, using the following keywords combinations: "mood disorder", "bipolar disorder", "depression", "unipolar disorder", "major depressive disorder", "affective disorder", for psychiatric conditions; and "circadian rhythms", "circadian markers", "circadian gene", "clock gene", "melatonin" for circadian rhythms. The search critera was presence of word in any field of the article. Quantitative and qualitative circadian abnormalities are associated with bipolar disorders both during acute episodes and euthymic periods, suggesting that these altered circadian rhythms may represent biological trait markers of the disorder. These circadian dysfunctions were assessed by various validated tools including polysomnography, actigraphy, sleep diaries, chronotype assessments and blood melatonin/cortisol measures. Other altered endogenous circadian activities have also been reported in bipolar patients, such as hormones secretion, core body temperature or fibroblasts activity. Moreover, these markers were also altered in healthy relatives of bipolar patients, suggesting a degree of heritability. Several genetic association studies have also showed associations between multiple circadian genes and bipolar disorder, such as CLOCK, ARTNL1, GSK3β, PER3, NPAS2, NR1D1, TIMELESS, RORA, RORB, and CSNK1ε. Thus, these circadian gene variants may contribute to the genetic susceptibility of the disease. Furthermore, the study of the clock system may help to better understand some phenotypic aspects like the

  16. Processamento cognitivo "Teoria da Mente" no transtorno bipolar Cognitive "Theory of Mind" processing in bipolar disorder

    Directory of Open Access Journals (Sweden)

    Hélio Anderson Tonelli

    2009-12-01

    Full Text Available OBJETIVO: O transtorno afetivo bipolar está associado ao comprometimento funcional persistente. Apesar de muitas pesquisas demonstrarem que bipolares podem apresentar déficits cognitivos, um número menor de trabalhos avaliou o papel de prejuízos no processamento cognitivo social, a Teoria da Mente (relacionado à capacidade de inferir estados mentais, no aparecimento de sintomas e complicações sociais em bipolares. O objetivo deste trabalho é o de revisar sistemática e criticamente a literatura sobre possíveis alterações do processamento Teoria da Mente no transtorno afetivo bipolar. MÉTODO: Foi realizada uma busca na base de dados Medline por trabalhos publicados em língua inglesa, alemã, espanhola ou portuguesa nos últimos 20 anos, utilizando a frase de busca "Bipolar Disorder"[Mesh] AND "Theory of Mind". Foram procurados por estudos clínicos envolvendo indivíduos bipolares e que empregaram uma ou mais tarefas cognitivas desenvolvidas para a avaliação de habilidades Teoria da Mente. Foram excluídos os relatos de caso e cartas ao editor. A busca inicial resultou em cinco artigos, sendo selecionados quatro. Outros quatro foram também selecionados a partir da leitura dos artigos acima. DISCUSSÃO: Os artigos selecionados avaliaram populações de bipolares adultos e pediátricos, incluindo indivíduos eutímicos, maníacos e deprimidos. A maioria dos trabalhos avaliados sugere que existam prejuízos no processamento Teoria da Mente em portadores de transtorno afetivo bipolar e que estes podem estar por trás dos sintomas e dos déficits funcionais do transtorno afetivo bipolar. CONCLUSÃO: Pesquisas futuras a respeito do tema em questão poderão esclarecer muito acerca do papel das alterações sociocognitivas no surgimento dos sintomas do transtorno afetivo bipolar, bem como ajudar no desenvolvimento de estratégias preventivas e terapêuticas do mesmo.OBJECTIVE: Bipolar disorder is associated to persistent functional

  17. Electrically induced phase transition in GeSbTe alloys

    Energy Technology Data Exchange (ETDEWEB)

    Bruns, Gunnar; Schlockermann, Carl; Woda, Michael; Wuttig, Matthias [I. Physikalisches Institut Ia, RWTH Aachen, 52056 Aachen (Germany)

    2008-07-01

    While phase change materials have already successfully been applied in rewriteable optical data storage, they are now also promising to form the basis for novel non-volatile electrical data storage devices. To understand the physical concepts of these so-called Phase Change Random Access Memory (PCRAM) it is mandatory to gain a deeper insight into the switching process between the highly resistive amorphous and the lowly resistive crystalline phase. The fast phase transitions between the amorphous and crystalline state of GeSbTe-based alloys has so far often been studied using pulsed laser irradiation. In this work an alternative approach is employed to investigate this transition. Electrical pulses are used to rapidly and reversibly switch between the two states. For these experiments a setup was built with a specially designed contacting circuit board to meet the requirements of electrical measurements on a nanosecond timescale. The influence of the pulse parameters on the change of device resistance was determined for different initial states. Furthermore the high time resolution of 0.4 ns allows investigation of transient electrical effects like the so-called threshold switching first described by Ovshinsky in the late 1960s.

  18. Ab initio simulation of amorphous silicon

    International Nuclear Information System (INIS)

    Cooper, N.C.; McKenzie, D.R.; Goringe, C.M.

    1999-01-01

    Full text: A first-principles Car-Parrinello molecular dynamics simulation of amorphous silicon is presented. Density Functional Theory is used to describe the forces between the atoms in a 64 atom supercell which is periodically repeated throughout space in order to generate an infinite network of atoms (a good approximation to a real solid). A quench from the liquid phase is used to achieve a quenched amorphous structure, which is subjected to an annealing cycle to improve its stability. The final, annealed network is in better agreement with experiment than any previous simulation of amorphous silicon. Significantly, the predicted average first-coordination numbers of 3.56 and 3.84 for the quenched and annealed structures from this simulation agree very closely with the experimental values of 3.55 and 3.90 respectively, whereas all previous simulations yielded first coordination numbers greater than 4. This improved agreement in coordination numbers is important because it supports the experimental finding that dangling bonds (which are associated with under-coordinated atoms) are more prevalent than floating bonds (the strained, longer bond of a five coordinate atom) in pure amorphous silicon. Finally, the effect of adding hydrogen to amorphous silicon was investigated by specifically placing hydrogen atoms at the likely defect sites. After a structural relaxation to optimise the positions of these hydrogen atoms, the localised electronic states associated with these defects are absent. Thus hydrogen is responsible for removing these defect states (which are able to trap carriers) from the edge of the band gap of the amorphous silicon. These results confirm the widely held ideas about the effect of hydrogen in producing remarkable improvements in the electronic properties of amorphous silicon

  19. Effects of the amorphization on hysteresis loops of the amorphous spin-1/2 Ising system

    International Nuclear Information System (INIS)

    Essaoudi, I.; Ainane, A.; Saber, M.; Miguel, J.J. de

    2009-01-01

    We examine the effects of the amorphization on the hysteresis loops of the amorphous spin-1/2 Ising system using the effective field theory within a probability distribution technique that accounts for the self-spin correlation functions. The magnetization, the transverse and longitudinal susceptibilities, and pyromagnetic coefficient are also studied in detail

  20. The International Society for Bipolar Disorders (ISBD) Task Force Report on Antidepressant Use in Bipolar Disorders

    Science.gov (United States)

    Pacchiarotti, Isabella; Bond, David J.; Baldessarini, Ross J.; Nolen, Willem A.; Grunze, Heinz; Licht, Rasmus W.; Post, Robert M.; Berk, Michael; Goodwin, Guy M.; Sachs, Gary S.; Tondo, Leonardo; Findling, Robert L.; Youngstrom, Eric A.; Tohen, Mauricio; Undurraga, Juan; González-Pinto, Ana; Goldberg, Joseph F.; Yildiz, Ayşegül; Altshuler, Lori L.; Calabrese, Joseph R.; Mitchell, Philip B.; Thase, Michael E.; Koukopoulos, Athanasios; Colom, Francesc; Frye, Mark A.; Malhi, Gin S.; Fountoulakis, Konstantinos N.; Vázquez, Gustavo; Perlis, Roy H.; Ketter, Terence A.; Cassidy, Frederick; Akiskal, Hagop; Azorin, Jean-Michel; Valentí, Marc; Mazzei, Diego Hidalgo; Lafer, Beny; Kato, Tadafumi; Mazzarini, Lorenzo; Martínez-Aran, Anabel; Parker, Gordon; Souery, Daniel; Özerdem, Ayşegül; McElroy, Susan L.; Girardi, Paolo; Bauer, Michael; Yatham, Lakshmi N.; Zarate, Carlos A.; Nierenberg, Andrew A.; Birmaher, Boris; Kanba, Shigenobu; El-Mallakh, Rif S.; Serretti, Alessandro; Rihmer, Zoltan; Young, Allan H.; Kotzalidis, Georgios D.; MacQueen, Glenda M.; Bowden, Charles L.; Ghaemi, S. Nassir; Lopez-Jaramillo, Carlos; Rybakowski, Janusz; Ha, Kyooseob; Perugi, Giulio; Kasper, Siegfried; Amsterdam, Jay D.; Hirschfeld, Robert M.; Kapczinski, Flávio; Vieta, Eduard

    2014-01-01

    Objective The risk-benefit profile of antidepressant medications in bipolar disorder is controversial. When conclusive evidence is lacking, expert consensus can guide treatment decisions. The International Society for Bipolar Disorders (ISBD) convened a task force to seek consensus recommendations on the use of antidepressants in bipolar disorders. Method An expert task force iteratively developed consensus through serial consensus-based revisions using the Delphi method. Initial survey items were based on systematic review of the literature. Subsequent surveys included new or reworded items and items that needed to be rerated. This process resulted in the final ISBD Task Force clinical recommendations on antidepressant use in bipolar disorder. Results There is striking incongruity between the wide use of and the weak evidence base for the efficacy and safety of antidepressant drugs in bipolar disorder. Few well-designed, long-term trials of prophylactic benefits have been conducted, and there is insufficient evidence for treatment benefits with antidepressants combined with mood stabilizers. A major concern is the risk for mood switch to hypomania, mania, and mixed states. Integrating the evidence and the experience of the task force members, a consensus was reached on 12 statements on the use of antidepressants in bipolar disorder. Conclusions Because of limited data, the task force could not make broad statements endorsing antidepressant use but acknowledged that individual bipolar patients may benefit from antidepressants. Regarding safety, serotonin reuptake inhibitors and bupropion may have lower rates of manic switch than tricyclic and tetracyclic antidepressants and norepinephrine-serotonin reuptake inhibitors. The frequency and severity of antidepressant-associated mood elevations appear to be greater in bipolar I than bipolar II disorder. Hence, in bipolar I patients antidepressants should be prescribed only as an adjunct to mood-stabilizing medications

  1. Segregation of Ge in B and Ge codoped Czochralski-Si crystal growth

    International Nuclear Information System (INIS)

    Arivanandhan, Mukannan; Gotoh, Raira; Fujiwara, Kozo; Uda, Satoshi; Hayakawa, Yasuhiro

    2015-01-01

    Highlights: • Effective segregation of Ge in B and Ge codoped Czochralski-Si crystal growth was analyzed. • The equilibrium segregation coefficient of Ge was calculated. • The experimentally results were analytically analyzed using partitioning theory. - Abstract: The segregation of Ge in B and Ge codoped Czochralski (CZ)-Si crystal growth was investigated. The concentration of Ge in heavily Ge codoped CZ-Si was measured by electron probe micro analysis (EPMA) and X-ray fluorescence spectroscopy. The effective segregation coefficient of Ge (k eff ) was calculated by fitting the EPMA data to the normal freezing equation, and by taking the logarithmic ratio of the Ge concentrations at the seed and tail of the ingots (top to bottom approach). The k eff of Ge increased from 0.30 to 0.55, when the initial Ge concentration in the Si melt (C L(o) Ge ) was increased from 3 × 10 19 to 3 × 10 21 cm −3 . To avoid cellular growth, the crystal pulling rate was decreased for heavily Ge codoped crystal growth (C L(o) Ge > 3 × 10 20 cm −3 ). The equilibrium segregation coefficient (k 0 ) of Ge was calculated by partitioning theory, and was smaller than the experimentally estimated k eff . The variation of k eff from k 0 was discussed based on Ge clustering in the heavily Ge codoped crystal, which led to changes in the bonding and strain energies caused by the incorporation of Ge into Si

  2. Iron-based amorphous alloys and methods of synthesizing iron-based amorphous alloys

    Science.gov (United States)

    Saw, Cheng Kiong; Bauer, William A.; Choi, Jor-Shan; Day, Dan; Farmer, Joseph C.

    2016-05-03

    A method according to one embodiment includes combining an amorphous iron-based alloy and at least one metal selected from a group consisting of molybdenum, chromium, tungsten, boron, gadolinium, nickel phosphorous, yttrium, and alloys thereof to form a mixture, wherein the at least one metal is present in the mixture from about 5 atomic percent (at %) to about 55 at %; and ball milling the mixture at least until an amorphous alloy of the iron-based alloy and the at least one metal is formed. Several amorphous iron-based metal alloys are also presented, including corrosion-resistant amorphous iron-based metal alloys and radiation-shielding amorphous iron-based metal alloys.

  3. Bipolar postpartum depression: An update and recommendations.

    Science.gov (United States)

    Sharma, Verinder; Doobay, Minakshi; Baczynski, Christine

    2017-09-01

    Over the past few years there has been a surge of interest in the study of bipolar postpartum depression (PPD); however, questions remain about its prevalence, screening, clinical features, and treatment. Three electronic databases, MEDLINE/PubMed (1966-2016), PsycINFO (1806-2016), and the Cochrane Database of Systematic Reviews, were searched using a combination of the keywords bipolar, depression, postpartum, peripartum, prevalence, screening, diagnosis, treatment, drugs, and psychotherapy. The reference lists of articles identified were also searched. All relevant articles published in English were included. Depending on the population studied, 21.4-54% of women with PPD have a diagnosis of bipolar disorder (BD). Characteristic clinical features include younger age at illness onset, first onset of depression after childbirth, onset immediately after delivery, atypical depressive symptoms, psychotic features, mixed features, and history of BD in first-degree family members. Treatment should be guided by symptom acuity, safety concerns, the patient's response to past treatments, drug tolerability, and breastfeeding preference. In the absence of controlled treatment data, preference should be given to drugs normally indicated for bipolar depression including lithium, quetiapine and lamotrigine. Although antidepressants have been studied in combination with mood stabilizers in bipolar depression, these drugs should be avoided due to likelihood of elevated risk of induction of manic symptoms in the postpartum period. In the postpartum period, bipolar PPD is common, can be differentiated from unipolar PPD, and needs to be identified promptly in order to expedite appropriate treatment. Future studies on pharmacotherapy and psychotherapy should focus on the acute and preventative treatment of bipolar PPD. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Relation between bandgap and resistance drift in amorphous phase change materials.

    Science.gov (United States)

    Rütten, Martin; Kaes, Matthias; Albert, Andreas; Wuttig, Matthias; Salinga, Martin

    2015-12-01

    Memory based on phase change materials is currently the most promising candidate for bridging the gap in access time between memory and storage in traditional memory hierarchy. However, multilevel storage is still hindered by the so-called resistance drift commonly related to structural relaxation of the amorphous phase. Here, we present the temporal evolution of infrared spectra measured on amorphous thin films of the three phase change materials Ag4In3Sb67Te26, GeTe and the most popular Ge2Sb2Te5. A widening of the bandgap upon annealing accompanied by a decrease of the optical dielectric constant ε∞ is observed for all three materials. Quantitative comparison with experimental data for the apparent activation energy of conduction reveals that the temporal evolution of bandgap and activation energy can be decoupled. The case of Ag4In3Sb67Te26, where the increase of activation energy is significantly smaller than the bandgap widening, demonstrates the possibility to identify new phase change materials with reduced resistance drift.

  5. The microstructure investigation of GeTi thin film used for non-volatile memory

    International Nuclear Information System (INIS)

    Shen Jie; Liu Bo; Song Zhitang; Xu Cheng; Liang Shuang; Feng Songlin; Chen Bomy

    2008-01-01

    GeTi thin film has been found to have the reversible resistance switching property in our previous work. In this paper, the microstructure of this material with a given composition was investigated. The film was synthesized by magnetron sputtering and treated by the rapid temperature process. The results indicate a coexist status of amorphous and polycrystalline states in the as-deposited GeTi film, and the grains in the film are extremely fine. Furthermore, not until the film annealed at 600 deg. C, can the polycrystalline state be detected by X-ray diffraction. Based on the morphological analysis, the sputtered GeTi has the column growth tendency, and the column structure vanishes with the temperature increasing. The microstructure and thermal property analysis indicate that GeTi does not undergo evident phase change process during the annealing process, which makes the switching mechanism of GeTi different from that of chalcogenide memory material, the most widely used phase change memory material

  6. The relationship between structural and optical properties of Se-Ge-As glasses

    Science.gov (United States)

    Ghayebloo, M.; Rezvani, M.; Tavoosi, M.

    2018-05-01

    In this study, the structural and optical characterization of bulk Se-Ge-As glasses has been investigated. In this regards, six different Se60Ge40-xAsx (0 ≤ x ≤ 25) glasses were prepared by conventional melt quenching technique in quartz ampoule. The produced samples were characterized using X-ray diffraction (XRD), Raman spectroscopy, differential thermal analysis (DTA), ultraviolet-visible (UV-Vis) and Fourier transform infrared (FTIR) spectroscopy. The fundamental absorption edge for all the glasses was analyzed in terms of the theory proposed by Davis and Mott. According to achieved results, fully amorphous phase can easily form in different Se-Ge-As systems. The thermal and optical characteristic of Se60Ge40-xAsx glasses shows anomalous behavior at 5 mol% of As for the glass transition temperature, transmittance, absorption edge, optical energy gap and Urbach energy. The highest glass transition temperature, transmittance, optical energy gap and Urbach energy properties were achieved in Se60Ge35As5 glass as a result of the highest connectivity of cations and anions in glass network.

  7. NO2 gas sorption studies of Ge33Se67 films using quartz crystal microbalance

    International Nuclear Information System (INIS)

    Georgieva, Velichka; Mitkova, Maria; Chen, Ping; Tenne, Dmitri; Wolf, Kasandra; Gadjanova, Victoria

    2012-01-01

    A study on the NO 2 gas sorption ability of amorphous Ge 33 Se 67 coated quartz crystal microbalance (QCM) is presented. The thin films have been characterized before and after sorption/desorption processes of NO 2 by energy-dispersive X-ray spectroscopy (EDS), grazing angle X-ray diffraction (GAXRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and atom force microscopy (AFM) measurements. These studies indicated that physisorption occurs when NO 2 gas molecules are introduced into the chalcogenide film and the thin film composition or structure do not change. The mass loading due to NO 2 gas sorption was calculated by the resonator’s frequency shift. At the conditions of our experiment, up to 6.8 ng of the gas was sorbed into 200 nm thick Ge 33 Se 67 film at 5000 ppm NO 2 concentration. It has been established that the process of gas molecules sorption is reversible. Highlights: ► Ge 33 Se 67 thin film and quartz crystal microbalance for NO 2 gas sensing. ► Physisorption of NO 2 in Ge 33 Se 67 thin films. ► Reversibility of the NO 2 sorption in Ge 33 Se 67 thin films. ► Pure physical effect of gas sorption revealed by Raman, XPS, AFM. ► Large free volume of the thin films encountered through GAXRD.

  8. Electrical conductivity of ion irradiated Ge{sub 20}Se{sub 80-x}Bi{sub x} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Pratibha; Vashistha, Manvendra; Jain, I.P.I.P. E-mail: ipjain46@sify.com

    2003-06-01

    Amorphous chalcogenide semiconductor Ge{sub 20}Se{sub 80-x}Bi{sub x} thin films have been bombarded with 75 MeV Ni ions at room temperature. The ion irradiation induced effects on the electronic properties have been monitored by DC conductivity measurements over a temperature range of 77-476 K. The electrical conductivity and conduction activation energy changes on irradiation.

  9. Ta-based amorphous metal thin films

    Energy Technology Data Exchange (ETDEWEB)

    McGlone, John M., E-mail: mcglone@eecs.oregonstate.edu [School of Electrical Engineering and Computer Science, Oregon State University, Corvallis, OR 97331-5501 (United States); Olsen, Kristopher R. [Department of Chemistry, Oregon State University, Corvallis, OR 97331-4003 (United States); Stickle, William F.; Abbott, James E.; Pugliese, Roberto A.; Long, Greg S. [Hewlett-Packard Company, Corvallis, OR, 97333 (United States); Keszler, Douglas A. [Department of Chemistry, Oregon State University, Corvallis, OR 97331-4003 (United States); Wager, John F. [School of Electrical Engineering and Computer Science, Oregon State University, Corvallis, OR 97331-5501 (United States)

    2015-11-25

    With their lack of grains and grain boundaries, amorphous metals are known to possess advantageous mechanical properties and enhanced chemical stability relative to crystalline metals. Commonly, however, they exhibit poor high-temperature stability because of their metastable nature. Here, we describe two new Ta-based ternary metal thin films that retain thermal stability to 600 °C and above. The new thin-film compositions, Ta{sub 2}Ni{sub 2}Si{sub 1} and Ta{sub 2}Mo{sub 2}Si{sub 1}, are amorphous, exhibiting ultra-smooth surfaces (<0.4 nm) and resistivities typical of amorphous metals (224 and 177 μΩ cm, respectively). - Highlights: • New Ta-based amorphous metals were sputter deposited from individual targets. • As-deposited amorphous structure was confirmed through diffraction techniques. • Electrical and surface properties were characterized and possess smooth surfaces. • No evidence of crystallization up to 600 °C (TaNiSi) and 800 °C (TaMoSi). • Ultra-smooth surfaces remained unchanged up to crystallization temperature.

  10. Amorphous silicon detectors in positron emission tomography

    International Nuclear Information System (INIS)

    Conti, M.; Perez-Mendez, V.

    1989-12-01

    The physics of the detection process is studied and the performances of different Positron Emission Tomography (PET) system are evaluated by theoretical calculation and/or Monte Carlo Simulation (using the EGS code) in this paper, whose table of contents can be summarized as follows: a brief introduction to amorphous silicon detectors and some useful equation is presented; a Tantalum/Amorphous Silicon PET project is studied and the efficiency of the systems is studied by Monte Carlo Simulation; two similar CsI/Amorphous Silicon PET projects are presented and their efficiency and spatial resolution are studied by Monte Carlo Simulation, light yield and time characteristics of the scintillation light are discussed for different scintillators; some experimental result on light yield measurements are presented; a Xenon/Amorphous Silicon PET is presented, the physical mechanism of scintillation in Xenon is explained, a theoretical estimation of total light yield in Xenon and the resulting efficiency is discussed altogether with some consideration of the time resolution of the system; the amorphous silicon integrated electronics is presented, total noise and time resolution are evaluated in each of our applications; the merit parameters ε 2 τ's are evaluated and compared with other PET systems and conclusions are drawn; and a complete reference list for Xenon scintillation light physics and its applications is presented altogether with the listing of the developed simulation programs

  11. Amorphous silicon detectors in positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Conti, M. (Istituto Nazionale di Fisica Nucleare, Pisa (Italy) Lawrence Berkeley Lab., CA (USA)); Perez-Mendez, V. (Lawrence Berkeley Lab., CA (USA))

    1989-12-01

    The physics of the detection process is studied and the performances of different Positron Emission Tomography (PET) system are evaluated by theoretical calculation and/or Monte Carlo Simulation (using the EGS code) in this paper, whose table of contents can be summarized as follows: a brief introduction to amorphous silicon detectors and some useful equation is presented; a Tantalum/Amorphous Silicon PET project is studied and the efficiency of the systems is studied by Monte Carlo Simulation; two similar CsI/Amorphous Silicon PET projects are presented and their efficiency and spatial resolution are studied by Monte Carlo Simulation, light yield and time characteristics of the scintillation light are discussed for different scintillators; some experimental result on light yield measurements are presented; a Xenon/Amorphous Silicon PET is presented, the physical mechanism of scintillation in Xenon is explained, a theoretical estimation of total light yield in Xenon and the resulting efficiency is discussed altogether with some consideration of the time resolution of the system; the amorphous silicon integrated electronics is presented, total noise and time resolution are evaluated in each of our applications; the merit parameters {epsilon}{sup 2}{tau}'s are evaluated and compared with other PET systems and conclusions are drawn; and a complete reference list for Xenon scintillation light physics and its applications is presented altogether with the listing of the developed simulation programs.

  12. The Structure of Liquid and Amorphous Hafnia

    Directory of Open Access Journals (Sweden)

    Leighanne C. Gallington

    2017-11-01

    Full Text Available Understanding the atomic structure of amorphous solids is important in predicting and tuning their macroscopic behavior. Here, we use a combination of high-energy X-ray diffraction, neutron diffraction, and molecular dynamics simulations to benchmark the atomic interactions in the high temperature stable liquid and low-density amorphous solid states of hafnia. The diffraction results reveal an average Hf–O coordination number of ~7 exists in both the liquid and amorphous nanoparticle forms studied. The measured pair distribution functions are compared to those generated from several simulation models in the literature. We have also performed ab initio and classical molecular dynamics simulations that show density has a strong effect on the polyhedral connectivity. The liquid shows a broad distribution of Hf–Hf interactions, while the formation of low-density amorphous nanoclusters can reproduce the sharp split peak in the Hf–Hf partial pair distribution function observed in experiment. The agglomeration of amorphous nanoparticles condensed from the gas phase is associated with the formation of both edge-sharing and corner-sharing HfO6,7 polyhedra resembling that observed in the monoclinic phase.

  13. Big data for bipolar disorder.

    Science.gov (United States)

    Monteith, Scott; Glenn, Tasha; Geddes, John; Whybrow, Peter C; Bauer, Michael

    2016-12-01

    The delivery of psychiatric care is changing with a new emphasis on integrated care, preventative measures, population health, and the biological basis of disease. Fundamental to this transformation are big data and advances in the ability to analyze these data. The impact of big data on the routine treatment of bipolar disorder today and in the near future is discussed, with examples that relate to health policy, the discovery of new associations, and the study of rare events. The primary sources of big data today are electronic medical records (EMR), claims, and registry data from providers and payers. In the near future, data created by patients from active monitoring, passive monitoring of Internet and smartphone activities, and from sensors may be integrated with the EMR. Diverse data sources from outside of medicine, such as government financial data, will be linked for research. Over the long term, genetic and imaging data will be integrated with the EMR, and there will be more emphasis on predictive models. Many technical challenges remain when analyzing big data that relates to size, heterogeneity, complexity, and unstructured text data in the EMR. Human judgement and subject matter expertise are critical parts of big data analysis, and the active participation of psychiatrists is needed throughout the analytical process.

  14. Bipolar disorder and neurophysiologic mechanisms

    Science.gov (United States)

    McCrea, Simon M

    2008-01-01

    Recent studies have suggested that some variants of bipolar disorder (BD) may be due to hyperconnectivity between orbitofrontal (OFC) and temporal pole (TP) structures in the dominant hemisphere. Some initial MRI studies noticed that there were corpus callosum abnormalities within specific regional areas and it was hypothesized that developmentally this could result in functional or effective connectivity changes within the orbitofrontal-basal ganglia-thalamocortical circuits. Recent diffusion tensor imaging (DTI) white matter fiber tractography studies may well be superior to region of interest (ROI) DTI in understanding BD. A “ventral semantic stream” has been discovered connecting the TP and OFC through the uncinate and inferior longitudinal fasciculi and the elusive TP is known to be involved in theory of mind and complex narrative understanding tasks. The OFC is involved in abstract valuation in goal and sub-goal structures and the TP may be critical in binding semantic memory with person–emotion linkages associated with narrative. BD patients have relative attenuation of performance on visuoconstructional praxis consistent with an atypical localization of cognitive functions. Multiple lines of evidence suggest that some BD alleles are being selected for which could explain the enhanced creativity in higher-ability probands. Associations between ROI’s that are not normally connected could explain the higher incidence of artistic aptitude, writing ability, and scientific achievements among some mood disorder subjects. PMID:19337455

  15. 76 FR 30573 - Airworthiness Directives; General Electric Company (GE) GE90-110B1 and GE90-115B Turbofan Engines

    Science.gov (United States)

    2011-05-26

    ... applies to General Electric Company (GE) GE90-110B1 and GE90-115B turbofan engines with high-pressure...-0278; Directorate Identifier 2010-NE-10-AD] RIN 2120-AA64 Airworthiness Directives; General Electric Company (GE) GE90- 110B1 and GE90-115B Turbofan Engines AGENCY: Federal Aviation Administration (FAA), DOT...

  16. Bipolar disorder: an update | Outhoff | South African Family Practice

    African Journals Online (AJOL)

    Bipolar disorder, characterised by alternating discrete episodes of (hypo)mania and depression, provides unique diagnostic and treatment challenges. Updated diagnostic (DSM-5) and current pharmacological treatment recommendations are briefly reviewed here. Keywords: bipolar disorder; diagnosis; evidence-based ...

  17. Cytokines in bipolar disorder vs. healthy control subjects

    DEFF Research Database (Denmark)

    Munkholm, Klaus; Braüner, Julie Vestergaard; Kessing, Lars Vedel

    2013-01-01

    Bipolar disorder may be associated with peripheral immune system dysfunction; however, results in individual studies are conflicting. Our aim was to systematically review evidence of peripheral cytokine alterations in bipolar disorder integrating findings from various affective states....

  18. Assessment of subjective and objective cognitive function in bipolar disorder

    DEFF Research Database (Denmark)

    Demant, Kirsa M; Vinberg, Maj; Kessing, Lars V

    2015-01-01

    Cognitive dysfunction is prevalent in bipolar disorder (BD). However, the evidence regarding the association between subjective cognitive complaints, objective cognitive performance and psychosocial function is sparse and inconsistent. Seventy seven patients with bipolar disorder who presented...

  19. Application of Bipolar Fuzzy Sets in Graph Structures

    Directory of Open Access Journals (Sweden)

    Muhammad Akram

    2016-01-01

    Full Text Available A graph structure is a useful tool in solving the combinatorial problems in different areas of computer science and computational intelligence systems. In this paper, we apply the concept of bipolar fuzzy sets to graph structures. We introduce certain notions, including bipolar fuzzy graph structure (BFGS, strong bipolar fuzzy graph structure, bipolar fuzzy Ni-cycle, bipolar fuzzy Ni-tree, bipolar fuzzy Ni-cut vertex, and bipolar fuzzy Ni-bridge, and illustrate these notions by several examples. We study ϕ-complement, self-complement, strong self-complement, and totally strong self-complement in bipolar fuzzy graph structures, and we investigate some of their interesting properties.

  20. Cardiovascular risk factors in outpatients with bipolar disorder

    NARCIS (Netherlands)

    Klumpers, U.M.H.; Boom, K.; Janssen, F.M.G.; Tulen, J.H.M.; Loonen, Anton J. M.

    2004-01-01

    Background: The mortality due to cardiovascular diseases in bipolar patients is much higher than in the general population. It is unclear whether lithium treatment contributes to this cardiovascular morbidity. Methods: The cardiovascular risk factors in outpatients with bipolar disorder on

  1. Mn-doped Ge self-assembled quantum dots via dewetting of thin films

    Science.gov (United States)

    Aouassa, Mansour; Jadli, Imen; Bandyopadhyay, Anup; Kim, Sung Kyu; Karaman, Ibrahim; Lee, Jeong Yong

    2017-03-01

    In this study, we demonstrate an original elaboration route for producing a Mn-doped Ge self-assembled quantum dots on SiO2 thin layer for MOS structure. These magnetic quantum dots are elaborated using dewetting phenomenon at solid state by Ultra-High Vacuum (UHV) annealing at high temperature of an amorphous Ge:Mn (Mn: 40%) nanolayer deposed at very low temperature by high-precision Solid Source Molecular Beam Epitaxy on SiO2 thin film. The size of quantum dots is controlled with nanometer scale precision by varying the nominal thickness of amorphous film initially deposed. The magnetic properties of the quantum-dots layer have been investigated by superconducting quantum interference device (SQUID) magnetometry. Atomic force microscopy (AFM), x-ray energy dispersive spectroscopy (XEDS) and transmission electron microscopy (TEM) were used to examine the nanostructure of these materials. Obtained results indicate that GeMn QDs are crystalline, monodisperse and exhibit a ferromagnetic behavior with a Curie temperature (TC) above room temperature. They could be integrated into spintronic technology.

  2. Comparative frequency-resolved photoconductivity studies of amorphous semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Kaplan, R. [Department of Secondary Science and Mathematics Education, University of Mersin, Yenisehir Campus, 33169 Mersin (Turkey)

    2005-02-01

    Comparative frequency-resolved photoconductivity measurements in amorphous (a-) semiconductors, such as a-Si:H p-i-n junction, a-SiGe:H and a-chalcogenides (a-Se, a-As{sub 2}Se{sub 3}, a-As{sub 2}Te{sub 3}, a-SeTe, a-As{sub 2}S{sub 3}, etc.) are reported. In particular, photoconductivity lifetimes as a function of light intensity and temperature were determined by using the quadrature frequency-resolved spectroscopy method. The activation energies from the temperature-dependent lifetime and photocurrent were determined and compared in different materials. The exponent n in the power-law relationship (I{sub ph}KG{sup n}) between generating flux and photocurrent was also obtained at different excitation wavelengths. The results were compared with the predictions of multiple-trapping (MT) and distant-pair (DP) models developed for photoconductivity of a-semiconductors at high and low temperatures, respectively.

  3. High-frequency noise modeling of Si(Ge) bipolar transistors

    NARCIS (Netherlands)

    Vitale, F.

    2014-01-01

    The design and the optimization of electronic systems often requires a detailed knowledge of the inherent noise generated within semiconductor active devices, constituting the core of such systems. Examples of applications in which noise is a key issue include receiver front-ends in radiofrequency

  4. Bipolar magnetic semiconductor in silicene nanoribbons

    Energy Technology Data Exchange (ETDEWEB)

    Farghadan, Rouhollah, E-mail: rfarghadan@kashanu.ac.ir

    2017-08-01

    Highlights: • A new electronic phase for silicene nanoribbon in the presence of electric and magnetic fields. • Bipolar magnetic semiconductor with controllable spin-flip and spin-conserved gaps in silicene. • Robust bipolar magnetic semiconductor features in a rough silicene. • Perfect and reversible spin polarization in silicene nanoribbon junctions. - Abstract: A theoretical study was presented on generation of spin polarization in silicene nanoribbons using the single-band tight-binding approximation and the non-equilibrium Green’s function formalism. We focused on the effect of electric and exchange magnetic fields on the spin-filter capabilities of zigzag-edge silicene nanoribbons in the presence of the intrinsic spin-orbit interaction. The results show that a robust bipolar magnetic semiconductor with controllable spin-flip and spin-conserved gaps can be obtained when exchange magnetic and electric field strengths are both larger than the intrinsic spin-orbit interaction. Therefore, zigzag silicene nanoribbons could act as bipolar and perfect spin filter devices with a large spin-polarized current and a reversible spin polarization in the vicinity of the Fermi energy. We also investigated the effect of edge roughness and found that the bipolar magnetic semiconductor features are robust against edge disorder in silicene nanoribbon junctions. These results may be useful in multifunctional spin devices based on silicene nanoribbons.

  5. Family History in Patients with Bipolar Disorder.

    Science.gov (United States)

    Özdemir, Osman; Coşkun, Salih; Aktan Mutlu, Elif; Özdemir, Pınar Güzel; Atli, Abdullah; Yilmaz, Ekrem; Keskin, Sıddık

    2016-09-01

    In this study, we aimed to better understand the genetic transmission of bipolar disorder by examining the family history of patients. Sixty-three patients with bipolar disorder and their families were included. The final sample comprised 156 bipolar patients and their family members. An inclusion criterion was the presence of bipolar disorder history in the family. The diagnosis of other family members was confirmed by analyzing their files, hospital records, and by calling them to the hospital. Sixty-five patients were women (41.6%) and 91 were men (58.3%) (ratio of men/women: 1.40). When analyzing the results in terms of the transition of disease from the mother's or father's side, similar results were obtained: 25 patients were from the mother's side and 25 patients were from the father's side in 63 cases. The results of our study support the fact that a significant relationship exists between the degree of kinship and the heritability of bipolar disorder and, furthermore, that the effect of the maternal and paternal sides is similar on the transmission of genetic susceptibility.

  6. [Drug Abuse Comorbidity in Bipolar Disorder].

    Science.gov (United States)

    Ortiz, Óscar Medina

    2012-06-01

    Drug use among patients with bipolar disorder is greater than the one observed in the general population; psychotic episodes are likely to occur after consumption. This has implications in the prevention, etiology, management, and treatment of the disease. Bipolar disorder pathology is likely to have positive response to pharmacological treatment. Therefore, identifying the strategies with better results to be applied in these patients is fundamental for psychiatrists and primary care physicians. Review literature in order to determine the prevalence and characteristics of drug abuse in patients with bipolar disorder and establish the pharmacological strategies that have produced better results. Literature review. A great variety of studies demonstrate the relationship between bipolar disorder and drug use disorder. These patients are hospitalized more frequently, have an earlier onset of the disease, and present a larger number of depressive episodes and suicide attempts which affect the course of the disease. The drug with better results in the treatment of these patients is Divalproate. Satisfactory results have been also obtained with other mood stabilizers such as carbamazepine, lamotrigine, and the antipsychotic aripiprazole. Substance abuse is present in a large number of patients with bipolar disorder. The Divalproate is the drug that has shown better results in the studies. Copyright © 2012 Asociación Colombiana de Psiquiatría. Publicado por Elsevier España. All rights reserved.

  7. Bipolar magnetic semiconductor in silicene nanoribbons

    International Nuclear Information System (INIS)

    Farghadan, Rouhollah

    2017-01-01

    Highlights: • A new electronic phase for silicene nanoribbon in the presence of electric and magnetic fields. • Bipolar magnetic semiconductor with controllable spin-flip and spin-conserved gaps in silicene. • Robust bipolar magnetic semiconductor features in a rough silicene. • Perfect and reversible spin polarization in silicene nanoribbon junctions. - Abstract: A theoretical study was presented on generation of spin polarization in silicene nanoribbons using the single-band tight-binding approximation and the non-equilibrium Green’s function formalism. We focused on the effect of electric and exchange magnetic fields on the spin-filter capabilities of zigzag-edge silicene nanoribbons in the presence of the intrinsic spin-orbit interaction. The results show that a robust bipolar magnetic semiconductor with controllable spin-flip and spin-conserved gaps can be obtained when exchange magnetic and electric field strengths are both larger than the intrinsic spin-orbit interaction. Therefore, zigzag silicene nanoribbons could act as bipolar and perfect spin filter devices with a large spin-polarized current and a reversible spin polarization in the vicinity of the Fermi energy. We also investigated the effect of edge roughness and found that the bipolar magnetic semiconductor features are robust against edge disorder in silicene nanoribbon junctions. These results may be useful in multifunctional spin devices based on silicene nanoribbons.

  8. Comorbid medical illness in bipolar disorder.

    Science.gov (United States)

    Forty, Liz; Ulanova, Anna; Jones, Lisa; Jones, Ian; Gordon-Smith, Katherine; Fraser, Christine; Farmer, Anne; McGuffin, Peter; Lewis, Cathryn M; Hosang, Georgina M; Rivera, Margarita; Craddock, Nick

    2014-12-01

    Individuals with a mental health disorder appear to be at increased risk of medical illness. To examine rates of medical illnesses in patients with bipolar disorder (n = 1720) and to examine the clinical course of the bipolar illness according to lifetime medical illness burden. Participants recruited within the UK were asked about the lifetime occurrence of 20 medical illnesses, interviewed using the Schedules for Clinical Assessment in Neuropsychiatry (SCAN) and diagnosed according to DSM-IV criteria. We found significantly increased rates of several medical illnesses in our bipolar sample. A high medical illness burden was associated with a history of anxiety disorder, rapid cycling mood episodes, suicide attempts and mood episodes with a typically acute onset. Bipolar disorder is associated with high rates of medical illness. This comorbidity needs to be taken into account by services in order to improve outcomes for patients with bipolar disorder and also in research investigating the aetiology of affective disorder where shared biological pathways may play a role. Royal College of Psychiatrists.

  9. High Growth Rate Deposition of Hydrogenated Amorphous Silicon-Germanium Films and Devices Using ECR-PECVD

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yong [Iowa State Univ., Ames, IA (United States)

    2002-01-01

    Hydrogenated amorphous silicon germanium films (a-SiGe:H) and devices have been extensively studied because of the tunable band gap for matching the solar spectrum and mature the fabrication techniques. a-SiGe:H thin film solar cells have great potential for commercial manufacture because of very low cost and adaptability to large-scale manufacturing. Although it has been demonstrated that a-SiGe:H thin films and devices with good quality can be produced successfully, some issues regarding growth chemistry have remained yet unexplored, such as the hydrogen and inert-gas dilution, bombardment effect, and chemical annealing, to name a few. The alloying of the SiGe introduces above an order-of-magnitude higher defect density, which degrades the performance of the a-SiGe:H thin film solar cells. This degradation becomes worse when high growth-rate deposition is required. Preferential attachment of hydrogen to silicon, clustering of Ge and Si, and columnar structure and buried dihydride radicals make the film intolerably bad. The work presented here uses the Electron-Cyclotron-Resonance Plasma-Enhanced Chemical Vapor Deposition (ECR-PECVD) technique to fabricate a-SiGe:H films and devices with high growth rates. Helium gas, together with a small amount of H2, was used as the plasma species. Thickness, optical band gap, conductivity, Urbach energy, mobility-lifetime product, I-V curve, and quantum efficiency were characterized during the process of pursuing good materials. The microstructure of the a-(Si,Ge):H material was probed by Fourier-Transform Infrared spectroscopy. They found that the advantages of using helium as the main plasma species are: (1) high growth rate--the energetic helium ions break the reactive gas more efficiently than hydrogen ions; (2) homogeneous growth--heavy helium ions impinging on the surface promote the surface mobility of the reactive radicals, so that heteroepitaxy growth as clustering of Ge and Si, columnar structure are

  10. Rumination in bipolar disorder: evidence for an unquiet mind

    OpenAIRE

    Ghaznavi, Sharmin; Deckersbach, Thilo

    2012-01-01

    Abstract Depression in bipolar disorder has long been thought to be a state characterized by mental inactivity. However, recent research demonstrates that patients with bipolar disorder engage in rumination, a form of self-focused repetitive cognitive activity, in depressed as well as in manic states. While rumination has long been associated with depressed states in major depressive disorder, the finding that patients with bipolar disorder ruminate in manic states is unique to bipolar disord...

  11. Voltage regulator for battery power source. [using a bipolar transistor

    Science.gov (United States)

    Black, J. M. (Inventor)

    1979-01-01

    A bipolar transistor in series with the battery as the control element also in series with a zener diode and a resistor is used to maintain a predetermined voltage until the battery voltage decays to very nearly the predetermined voltage. A field effect transistor between the base of the bipolar transistor and a junction between the zener diode and resistor regulates base current of the bipolar transistor, thereby regulating the conductivity of the bipolar transistor for control of the output voltage.

  12. Emerging trends in the stabilization of amorphous drugs

    DEFF Research Database (Denmark)

    Laitinen, Riikka; Löbmann, Korbinian; Strachan, Clare J.

    2013-01-01

    water-soluble drugs can be increased by the formation of stabilized amorphous forms. Currently, formulation as solid polymer dispersions is the preferred method to enhance drug dissolution and to stabilize the amorphous form of a drug. The purpose of this review is to highlight emerging alternative...... methods to amorphous polymer dispersions for stabilizing the amorphous form of drugs. First, an overview of the properties and stabilization mechanisms of amorphous forms is provided. Subsequently, formulation approaches such as the preparation of co-amorphous small-molecule mixtures and the use...

  13. Nanoscale density variations induced by high energy heavy ions in amorphous silicon nitride and silicon dioxide

    Science.gov (United States)

    Mota-Santiago, P.; Vazquez, H.; Bierschenk, T.; Kremer, F.; Nadzri, A.; Schauries, D.; Djurabekova, F.; Nordlund, K.; Trautmann, C.; Mudie, S.; Ridgway, M. C.; Kluth, P.

    2018-04-01

    The cylindrical nanoscale density variations resulting from the interaction of 185 MeV and 2.2 GeV Au ions with 1.0 μm thick amorphous SiN x :H and SiO x :H layers are determined using small angle x-ray scattering measurements. The resulting density profiles resembles an under-dense core surrounded by an over-dense shell with a smooth transition between the two regions, consistent with molecular-dynamics simulations. For amorphous SiN x :H, the density variations show a radius of 4.2 nm with a relative density change three times larger than the value determined for amorphous SiO x :H, with a radius of 5.5 nm. Complementary infrared spectroscopy measurements exhibit a damage cross-section comparable to the core dimensions. The morphology of the density variations results from freezing in the local viscous flow arising from the non-uniform temperature profile in the radial direction of the ion path. The concomitant drop in viscosity mediated by the thermal conductivity appears to be the main driving force rather than the presence of a density anomaly.

  14. Formation of amorphous layers by irradiation

    International Nuclear Information System (INIS)

    Bourgoin, J.C.

    1979-01-01

    When an ordered solid is irradiated with heavy energy particles, disorder is produced. When the irradiation dose exceeds a so-called critical dose, the irradiated area of the solid becomes uniformly disordered. Mention is first made of the nature, concentration and distribution of the defects created by a heavy energy particle. The description is then given -solely with respect to semiconductors- of the effect of the various parameters on the critical dose energy and nature of the ion, nature and temperature of the solid, irradiation flux. The physical properties (electronic and thermodynamic types) and the uniformly disordered areas are briefly discussed and these properties are compared with those of amorphous semiconductor layers fabricated by evaporation. It is concluded that the evaporated and irradiated layers are similar in nature. It is suggested that the transformation of an irradiated crystalline area into an amorphous one occurs when the Gibbs energy of the crystal become greater than the Gibbs energy of the amorphous one [fr

  15. Phase transitions in biogenic amorphous calcium carbonate.

    Science.gov (United States)

    Gong, Yutao U T; Killian, Christopher E; Olson, Ian C; Appathurai, Narayana P; Amasino, Audra L; Martin, Michael C; Holt, Liam J; Wilt, Fred H; Gilbert, P U P A

    2012-04-17

    Crystalline biominerals do not resemble faceted crystals. Current explanations for this property involve formation via amorphous phases. Using X-ray absorption near-edge structure (XANES) spectroscopy and photoelectron emission microscopy (PEEM), here we examine forming spicules in embryos of Strongylocentrotus purpuratus sea urchins, and observe a sequence of three mineral phases: hydrated amorphous calcium carbonate (ACC · H(2)O) → dehydrated amorphous calcium carbonate (ACC) → calcite. Unexpectedly, we find ACC · H(2)O-rich nanoparticles that persist after the surrounding mineral has dehydrated and crystallized. Protein matrix components occluded within the mineral must inhibit ACC · H(2)O dehydration. We devised an in vitro, also using XANES-PEEM, assay to identify spicule proteins that may play a role in stabilizing various mineral phases, and found that the most abundant occluded matrix protein in the sea urchin spicules, SM50, stabilizes ACC · H(2)O in vitro.

  16. Fabrication and application of amorphous semiconductor devices

    International Nuclear Information System (INIS)

    Kumurdjian, Pierre.

    1976-01-01

    This invention concerns the design and manufacture of elecric switching or memorisation components with amorphous semiconductors. As is known some compounds, particularly the chalcogenides, have a resistivity of the semiconductor type in the amorphous solid state. These materials are obtained by the high temperature homogeneisation of several single elements such as tellurium, arsenic, germanium and sulphur, followed by water or air quenching. In particular these compounds have useful switching and memorisation properties. In particular they have the characteristic of not suffering deterioration when placed in an environment subjected to nuclear radiations. In order to know more about the nature and properties of these amorphous semiconductors the French patent No. 71 28048 of 30 June 1971 may be consulted with advantage [fr

  17. Heavy ions amorphous semiconductors irradiation study

    International Nuclear Information System (INIS)

    Benmalek, M.

    1978-01-01

    The behavior of amorphous semiconductors (germanium and germanium and arsenic tellurides) under ion bombardment at energies up to 2 MeV was studied. The irradiation induced modifications were followed using electrical parameter changes (resistivity and activation energy) and by means of the transmission electron microscopy observations. The electrical conductivity enhancement of the irradiated samples was interpreted using the late conduction theories in amorphous compounds. In amorphous germanium, Electron Microscopy showed the formations of 'globules', these defects are similar to voids observed in irradiated metals. The displacement cascade theory was used for the interpretation of the irradiation induced defects formation and a coalescence mechanism of growth was pointed out for the vacancy agglomeration [fr

  18. Aqueous electrodeposition of Ge monolayers.

    Science.gov (United States)

    Liang, Xuehai; Kim, Youn-Geun; Gebergziabiher, Daniel K; Stickney, John L

    2010-02-16

    The electrodeposition of germanium on Au(111) in aqueous solutions has been investigated by means of cyclic voltammetry, Auger electron spectroscopy, and in situ scanning tunneling microscopy (STM). The data yield a picture of germanium deposition, which starts with the formation of two well-ordered hydroxide phases, with 1/3 ML and 4/9 ML coverages upon initial reduction of the Ge(IV) species (probably H(2)GeO(3) at pH 4.7). Those structures appear to result from a three-electron reduction to form surface-limited structures with (square root(3) x square root(3))R30 degrees or (3 x 3) unit cells, respectively. Further reduction, probably in a two-electron process from the hydroxide structures, resulted in a germanium hydride structure, again surface-limited, with a coverage of close to 0.8 ML. The hydride structure is very flat, though with the periodic modulation characteristic of a Moiré pattern. Longer deposition times and lower potentials resulted in increased coverage of Ge in some cases, but with apparently limited coverage as a function of pH. The maximum Ge coverage, about 4 ML, was observed using a pH 9.32 deposition solution. At potentials negative of the Moiré pattern, about -850 mV versus Ag/AgCl, a "corruption" of the smooth Moiré pattern occurred. This roughening appears to mark the initial formation of a Au-Ge alloy, accounting for the observation of coverage in excess of that needed to form the Moiré pattern at some pH values.

  19. High-Efficiency Amorphous Silicon Alloy Based Solar Cells and Modules; Final Technical Progress Report, 30 May 2002--31 May 2005

    Energy Technology Data Exchange (ETDEWEB)

    Guha, S.; Yang, J.

    2005-10-01

    The principal objective of this R&D program is to expand, enhance, and accelerate knowledge and capabilities for development of high-efficiency hydrogenated amorphous silicon (a-Si:H) and amorphous silicon-germanium alloy (a-SiGe:H) related thin-film multijunction solar cells and modules with low manufacturing cost and high reliability. Our strategy has been to use the spectrum-splitting triple-junction structure, a-Si:H/a-SiGe:H/a-SiGe:H, to improve solar cell and module efficiency, stability, and throughput of production. The methodology used to achieve the objectives included: (1) explore the highest stable efficiency using the triple-junction structure deposited using RF glow discharge at a low rate, (2) fabricate the devices at a high deposition rate for high throughput and low cost, and (3) develop an optimized recipe using the R&D batch large-area reactor to help the design and optimization of the roll-to-roll production machines. For short-term goals, we have worked on the improvement of a-Si:H and a-SiGe:H alloy solar cells. a-Si:H and a-SiGe:H are the foundation of current a-Si:H based thin-film photovoltaic technology. Any improvement in cell efficiency, throughput, and cost reduction will immediately improve operation efficiency of our manufacturing plant, allowing us to further expand our production capacity.

  20. Family Functioning and the Course of Adolescent Bipolar Disorder

    Science.gov (United States)

    Sullivan, Aimee E.; Judd, Charles M.; Axelson, David A.; Miklowitz, David J.

    2012-01-01

    The symptoms of bipolar disorder affect and are affected by the functioning of family environments. Little is known, however, about the stability of family functioning among youth with bipolar disorder as they cycle in and out of mood episodes. This study examined family functioning and its relationship to symptoms of adolescent bipolar disorder,…

  1. Coping and personality in older patients with bipolar disorder

    NARCIS (Netherlands)

    Schouws, S.N.T.M.; Paans, N.P.G.; Comijs, H.C.; Dols, A.; Stek, M.L.

    2015-01-01

    Abstract Background Little is known about coping styles and personality traits in older bipolar patients. Adult bipolar patients show a passive coping style and higher neuroticism scores compared to the general population. Our aim is to investigate personality traits and coping in older bipolar

  2. Dealing with bipolar disorder in general practice | Rodseth | South ...

    African Journals Online (AJOL)

    ... it is in the general realm of specialist diagnosis and care, general practitioners can play an important role in early identification of the disorder and long-term management, in shared care with the psychiatrist. Keywords: bipolar disorder, mania, hypomania, depression, DSM-IV criteria, bipolar I disorder, bipolar II disorder ...

  3. Competing covalent and ionic bonding in Ge-Sb-Te phase change materials.

    Science.gov (United States)

    Mukhopadhyay, Saikat; Sun, Jifeng; Subedi, Alaska; Siegrist, Theo; Singh, David J

    2016-05-19

    Ge2Sb2Te5 and related phase change materials are highly unusual in that they can be readily transformed between amorphous and crystalline states using very fast melt, quench, anneal cycles, although the resulting states are extremely long lived at ambient temperature. These states have remarkably different physical properties including very different optical constants in the visible in strong contrast to common glass formers such as silicates or phosphates. This behavior has been described in terms of resonant bonding, but puzzles remain, particularly regarding different physical properties of crystalline and amorphous phases. Here we show that there is a strong competition between ionic and covalent bonding in cubic phase providing a link between the chemical basis of phase change memory property and origins of giant responses of piezoelectric materials (PbTiO3, BiFeO3). This has important consequences for dynamical behavior in particular leading to a simultaneous hardening of acoustic modes and softening of high frequency optic modes in crystalline phase relative to amorphous. This different bonding in amorphous and crystalline phases provides a direct explanation for different physical properties and understanding of the combination of long time stability and rapid switching and may be useful in finding new phase change compositions with superior properties.

  4. Cryogenic ion implantation near amorphization threshold dose for halo/extension junction improvement in sub-30 nm device technologies

    International Nuclear Information System (INIS)

    Park, Hugh; Todorov, Stan; Colombeau, Benjamin; Rodier, Dennis; Kouzminov, Dimitry; Zou Wei; Guo Baonian; Khasgiwale, Niranjan; Decker-Lucke, Kurt

    2012-01-01

    We report on junction advantages of cryogenic ion implantation with medium current implanters. We propose a methodical approach on maximizing cryogenic effects on junction characteristics near the amorphization threshold doses that are typically used for halo implants for sub-30 nm technologies. BF 2 + implant at a dose of 8×10 13 cm −2 does not amorphize silicon at room temperature. When implanted at −100°C, it forms a 30 - 35 nm thick amorphous layer. The cryogenic BF 2 + implant significantly reduces the depth of the boron distribution, both as-implanted and after anneals, which improves short channel rolloff characteristics. It also creates a shallower n + -p junction by steepening profiles of arsenic that is subsequently implanted in the surface region. We demonstrate effects of implant sequences, germanium preamorphization, indium and carbon co-implants for extension/halo process integration. When applied to sequences such as Ge+As+C+In+BF 2 + , the cryogenic implants at −100°C enable removal of Ge preamorphization, and form more active n + -p junctions and steeper B and In halo profiles than sequences at room temperature.

  5. Short range order in amorphous polycondensates

    Energy Technology Data Exchange (ETDEWEB)

    Lamers, C.; Richter, D.; Schweika, W. [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Festkoerperforschung; Batoulis, J.; Sommer, K. [Bayer AG, Leverkusen (Germany); Cable, J.W. [Oak Ridge National Lab., TN (United States); Shapiro, S.M. [Brookhaven National Lab., Upton, NY (United States)

    1992-12-01

    The static coherent structure factors S(Q) of the polymer glass Bisphenol-A-Polycarbonate and its chemical variation Bisphenol-A- Polyctherkctone- both in differently deuterated versions- have been measured by spin polarized neutron scattering. The method of spin polarization analysis provided an experimental separation of coherent and incoherent scattering and a reliable intensity calibration. Results are compared to structure factors calculated for model structures which were obtained by ``amorphous cell`` computer simulations. In general reasonable agreement is found between experiment and simulation; however, certain discrepancies hint at an insufficient structural relaxation in the amorphous cell method. 15 refs, 1 fig, 1 tab.

  6. Ion bombardment and disorder in amorphous silicon

    International Nuclear Information System (INIS)

    Sidhu, L.S.; Gaspari, F.; Zukotynski, S.

    1997-01-01

    The effect of ion bombardment during growth on the structural and optical properties of amorphous silicon are presented. Two series of films were deposited under electrically grounded and positively biased substrate conditions. The biased samples displayed lower growth rates and increased hydrogen content relative to grounded counterparts. The film structure was examined using Raman spectroscopy. The transverse optic like phonon band position was used as a parameter to characterize network order. Biased samples displayed an increased order of the amorphous network relative to grounded samples. Furthermore, biased samples exhibited a larger optical gap. These results are correlated and attributed to reduced ion bombardment effects

  7. Amorphous Silicon-Carbon Nanostructure Photovoltaic Devices

    OpenAIRE

    Schriver, Maria Christine

    2012-01-01

    A novel solar cell architecture made completely from the earth abundant elements silicon and carbon has been developed. Hydrogenated amorphous silicon (aSi:H), rather than crystalline silicon, is used as the active material due to its high absorption through a direct band gap of 1.7eV, well matched to the solar spectrum to ensure the possibility of improved cells in this architecture with higher efficiencies. The cells employ a Schottky barrier design wherein the amorphous silicon absorber la...

  8. Irradiation induced crystalline to amorphous transition

    International Nuclear Information System (INIS)

    Bourgoin, J.

    1980-01-01

    Irradiation of a crystalline solid with energetic heavy particles results in cascades of defects which, with increasing dose, overlap and form a continuous disordered layer. In semiconductors the physical properties of such disordered layers are found to be similar to those of amorphous layers produced by evaporation. It is shown in the case of silicon, that the transition from a disordered crystalline (X) layer to an amorphous (α) layer occurs when the Gibbs energy of the X phase and of the defects it contains becomes larger than the Gibbs energy of the α phase. (author)

  9. Concurrent hypokalemic periodic paralysis and bipolar disorder

    Directory of Open Access Journals (Sweden)

    Chia-Lin Lin

    2015-01-01

    Full Text Available Primary periodic paralysis is a rare autosomal dominant disorder of ion-channel dysfunction, manifested by episodic flaccid paresis secondary to abnormal sarcolemma excitability. Membrane destabilization involving Na, K-ATPase has been hypothesized to be a biological etiology of the bipolar disorder (BD and the mechanisms underlying lithium therapy have been linked to it. To date, there has been only one reported case of BD comorbid with periodic paralysis. Herein, we reported another case of concurrent bipolar mania and hypokalemic periodic paralysis (HPP, one special form of periodic paralysis. Consistent with the previous case, our patient responded well to lithium treatment for both bipolar mania and HPP. This might provide some support to the hypothesis that the therapeutic effects of lithium in both BD and HPP could be due to the correction of the underlying common pathophysiology.

  10. Paired structures and bipolar knowledge representation

    DEFF Research Database (Denmark)

    Montero, Javier; Bustince, Humberto; Franco, Camilo

    In this strictly positional paper we propose a general approach to bipolar knowledge representation, where the meaning of concepts can be modelled by examining their decomposition into opposite and neutral categories. In particular, it is the semantic relationship between the opposite categories...... which suggests the emergence of a paired structure and its associated type of neutrality, being there three general types of neutral categories, namely indeterminacy, ambivalence and conflict. Hence, the key issue consists in identifying the semantic opposition characterizing the meaning of concepts...... and at the same time the type of neutrality rising in between opposites. Based on this first level of bipolar knowledge representation, paired structures in fact offer the means to characterize a specific bipolar valuation scale depending on the meaning of the concept that has to be verified. In this sense...

  11. Fenomenologia do tempo vivido no transtorno bipolar

    Directory of Open Access Journals (Sweden)

    Virginia Moreira

    Full Text Available Com base na tradição da psicopatologia fenomenológica, este artigo se propõe a contribuir para a compreensão do mundo vivido do paciente bipolar, marcado por uma forte alteração do tempo vivido. Realizamos uma descrição deste tempo vivido significado de forma diferente nas oscilações de humor chamadas de fase maníaca e fase melancólica. Pensado a partir da temporalidade, na fase melancólica, o bipolar parece parar no tempo, não se lança em um devir. Na fase maníaca, o sujeito vive demasiadamente um agora como se tivesse explodido sua biografia. Concluímos que estas fases, ou dois pólos opostos no funcionamento temporal patológico do sofrimento bipolar, constituem fundamentalmente um mesmo mundo vivido.

  12. Genetic structure of personality factors and bipolar disorder in families segregating bipolar disorder.

    Science.gov (United States)

    Hare, Elizabeth; Contreras, Javier; Raventos, Henriette; Flores, Deborah; Jerez, Alvaro; Nicolini, Humberto; Ontiveros, Alfonso; Almasy, Laura; Escamilla, Michael

    2012-02-01

    Bipolar disorder (BPD) has been associated with variations in personality dimensions, but the nature of this relationship has been unclear. In this study, the heritabilities of BPD and the Big Five personality factors and the genetic correlations between BPD and personality factors are reported. The participants in this study were 1073 individuals from 172 families of Mexican or Central American ancestry. Heritabilities and genetic correlations were calculated under a polygenic model using the maximum-likelihood method of obtaining variance components implemented in the SOLAR software package. Heritabilities of 0.49, 0.43, and 0.43 were found for the narrowest phenotype (schizoaffective bipolar and bipolar I), the intermediate phenotype (schizoaffective bipolar, bipolar I, and bipolar II), and the broadest phenotype (schizoaffective bipolar, bipolar I, bipolar II, and recurrent depression), respectively. For the Big Five personality factors, heritabilities were 0.25 for agreeableness, 0.24 for conscientiousness, 0.24 for extraversion, 0.23 for neuroticism, and 0.32 for openness to experience. For the narrowest phenotype, a significant negative correlation (-0.32) with extraversion was found. For the broadest phenotype, negative correlations were found for agreeableness (-0.35), conscientiousness (-0.39), and extraversion (-0.44). A positive correlation (0.37) was found with neuroticism. It is not possible to determine whether aspects of personality are factors in the development of bipolar disorder or vice versa. The short form of the NEO does not provide the ability to examine in detail which facets of extraversion are most closely related to bipolar disorder or to compare our results with studies that have used the long version of the scale. This study establishes a partial genetic basis for the Big Five personality factors in this set of families, while the environmental variances demonstrate that non-genetic factors are also important in their influence on

  13. Systematic review of the prevalence of bipolar disorder and bipolar spectrum disorders in population-based studies

    OpenAIRE

    Dell'Aglio Jr.,José Caetano; Basso,Lissia Ana; Argimon,Irani Iracema de Lima; Arteche,Adriane

    2013-01-01

    This paper describes the findings of a systematic literature review aimed at providing an overview of the lifetime prevalence of bipolar disorder and bipolar spectrum disorders in population-based studies. Databases MEDLINE, ProQuest, Psychnet, and Web of Science were browsed for papers published in English between 1999 and May 2012 using the following search string: bipolar disorders OR bipolar spectrum disorders AND prevalence OR cross-sectional OR epidemiology AND population-based OR non-c...

  14. Ultrafast terahertz-induced response of GeSbTe phase-change materials

    International Nuclear Information System (INIS)

    Shu, Michael J.; Zalden, Peter; Chen, Frank; Weems, Ben; Chatzakis, Ioannis; Xiong, Feng; Jeyasingh, Rakesh; Pop, Eric; Philip Wong, H.-S.; Hoffmann, Matthias C.; Wuttig, Matthias; Lindenberg, Aaron M.

    2014-01-01

    The time-resolved ultrafast electric field-driven response of crystalline and amorphous GeSbTe films has been measured all-optically, pumping with single-cycle terahertz pulses as a means of biasing phase-change materials on a sub-picosecond time-scale. Utilizing the near-band-gap transmission as a probe of the electronic and structural response below the switching threshold, we observe a field-induced heating of the carrier system and resolve the picosecond-time-scale energy relaxation processes and their dependence on the sample annealing condition in the crystalline phase. In the amorphous phase, an instantaneous electroabsorption response is observed, quadratic in the terahertz field, followed by field-driven lattice heating, with Ohmic behavior up to 200 kV/cm.

  15. Density functional simulations of hexagonal Ge2Sb2Te5 at high pressure

    Science.gov (United States)

    Caravati, Sebastiano; Sosso, Gabriele C.; Bernasconi, Marco; Parrinello, Michele

    2013-03-01

    We investigated the structural transformations of the hexagonal phase of Ge2Sb2Te5 under pressure by means of ab initio molecular dynamics with a variable simulation cell. To overcome the enthalpy barriers between the different phases we used metadynamics techniques. We reproduced the hexagonal-to-bcc transformation under pressure found experimentally. The bcc phase retains a partial chemical order, as opposed to a second bcc phase we generated by pressuring the amorphous phase. This structural difference is suggested to be responsible for the memory effect uncovered experimentally, the bcc phase reverting to the amorphous or to the hexagonal phase upon decompression, depending on the type of precursor phase it originates from.

  16. Metal-Insulator Transition Driven by Vacancy Ordering in GeSbTe Phase Change Materials.

    Science.gov (United States)

    Bragaglia, Valeria; Arciprete, Fabrizio; Zhang, Wei; Mio, Antonio Massimiliano; Zallo, Eugenio; Perumal, Karthick; Giussani, Alessandro; Cecchi, Stefano; Boschker, Jos Emiel; Riechert, Henning; Privitera, Stefania; Rimini, Emanuele; Mazzarello, Riccardo; Calarco, Raffaella

    2016-04-01

    Phase Change Materials (PCMs) are unique compounds employed in non-volatile random access memory thanks to the rapid and reversible transformation between the amorphous and crystalline state that display large differences in electrical and optical properties. In addition to the amorphous-to-crystalline transition, experimental results on polycrystalline GeSbTe alloys (GST) films evidenced a Metal-Insulator Transition (MIT) attributed to disorder in the crystalline phase. Here we report on a fundamental advance in the fabrication of GST with out-of-plane stacking of ordered vacancy layers by means of three distinct methods: Molecular Beam Epitaxy, thermal annealing and application of femtosecond laser pulses. We assess the degree of vacancy ordering and explicitly correlate it with the MIT. We further tune the ordering in a controlled fashion attaining a large range of resistivity. Employing ordered GST might allow the realization of cells with larger programming windows.

  17. Metal - Insulator Transition Driven by Vacancy Ordering in GeSbTe Phase Change Materials

    Science.gov (United States)

    Bragaglia, Valeria; Arciprete, Fabrizio; Zhang, Wei; Mio, Antonio Massimiliano; Zallo, Eugenio; Perumal, Karthick; Giussani, Alessandro; Cecchi, Stefano; Boschker, Jos Emiel; Riechert, Henning; Privitera, Stefania; Rimini, Emanuele; Mazzarello, Riccardo; Calarco, Raffaella

    2016-04-01

    Phase Change Materials (PCMs) are unique compounds employed in non-volatile random access memory thanks to the rapid and reversible transformation between the amorphous and crystalline state that display large differences in electrical and optical properties. In addition to the amorphous-to-crystalline transition, experimental results on polycrystalline GeSbTe alloys (GST) films evidenced a Metal-Insulator Transition (MIT) attributed to disorder in the crystalline phase. Here we report on a fundamental advance in the fabrication of GST with out-of-plane stacking of ordered vacancy layers by means of three distinct methods: Molecular Beam Epitaxy, thermal annealing and application of femtosecond laser pulses. We assess the degree of vacancy ordering and explicitly correlate it with the MIT. We further tune the ordering in a controlled fashion attaining a large range of resistivity. Employing ordered GST might allow the realization of cells with larger programming windows.

  18. Exercise in bipolar patients: A systematic review.

    Science.gov (United States)

    Melo, Matias Carvalho Aguiar; Daher, Elizabeth De Francesco; Albuquerque, Saulo Giovanni Castor; de Bruin, Veralice Meireles Sales

    2016-07-01

    Sedentary lifestyle is frequent in psychiatric disorders, however the directions of this association and benefits of physical activity are unclear. This is a systematic review about exercise in patients with bipolar disorder. We performed a systematic literature search of studies published in English (1995 Jan to 2016 Jan) in PubMed, and Cochrane Library combining the medical terms 'physical activity' or 'sedentary' or 'physical exercise' with 'bipolar disorder' or 'mania' or 'bipolar depression'. Thirty-one studies were selected and included 15,587 patients with bipolar disorder. Sedentary lifestyle varied from 40% to 64.9%. Physical activity was associated with less depressive symptoms, better quality of life and increased functioning. Some evidence indicates a relationship between vigorous exercises and mania. Three prospective cohorts were reported; and no prospective randomized controlled trial was identified. Three studies focused on biomarkers in bipolar patients; and one reported the relationship between exercise and sleep in this group. Two assessed physical exercise in adolescents. (1) Differences between studies preventing a unified analysis; (2) most studies were cross-sectional; (3) motivation for exercising is a selection bias in most studies; (4) no intervention study assessing only physical exercise; (5) lack of studies comparing exercise across mood states. Generally, exercise was associated with improved health measures including depressive symptoms, functioning and quality of life. Evidence was insufficient to establish a cause-effect relationship between mood and physical exercise. Future research including randomized trials is needed to clarify the role of physical activity in bipolar patients. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Radiation emission from wrinkled SiGe/SiGe nanostructure

    Czech Academy of Sciences Publication Activity Database

    Fedorchenko, Alexander I.; Cheng, H. H.; Sun, G.; Soref, R. A.

    2010-01-01

    Roč. 96, č. 11 (2010), s. 113104-113107 ISSN 0003-6951 Institutional research plan: CEZ:AV0Z20760514 Keywords : SiGe wrinkled nanostructures * si-based optical emitter * synchrotron radiation Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.820, year: 2010 http://apl.aip.org/resource/1/applab/v96/i11/p113104_s1?isAuthorized=no

  20. A report on older-age bipolar disorder from the International Society for Bipolar Disorders Task Force

    DEFF Research Database (Denmark)

    Sajatovic, Martha; Strejilevich, Sergio A; Gildengers, Ariel G

    2015-01-01

    OBJECTIVES: In the coming generation, older adults with bipolar disorder (BD) will increase in absolute numbers as well as proportion of the general population. This is the first report of the International Society for Bipolar Disorder (ISBD) Task Force on Older-Age Bipolar Disorder (OABD). METHO...

  1. Three times more days depressed than manic or hypomanic in both bipolar I and bipolar II disorder

    NARCIS (Netherlands)

    Kupka, Ralph W.; Altshuler, Lori L.; Nolen, Willem A.; Suppes, Trisha; Luckenbaugh, David A.; Leverich, Gabriele S.; Frye, Mark A.; Keck, Paul E.; McElroy, Susan L.; Grunze, Heinz; Post, Robert M.

    Objectives: To assess the proportion of time spent in mania, depression and euthymia in a large cohort of bipolar subjects studied longitudinally, and to investigate depression/mania ratios in patients with bipolar I versus bipolar II disorder. Methods: Clinician-adjusted self-ratings of mood were

  2. Alcoholism and anxiety in bipolar illness : Differential lifetime anxiety comorbidity in bipolar I women with and without alcoholism

    NARCIS (Netherlands)

    Levander, Eric; Frye, Mark A.; McElroy, Susan; Suppes, Trisha; Grunze, Heinz; Nolen, Willem A.; Kupka, Ralph; Keck, Paul E.; Leverich, Gabriele S.; Altshuler, Lori L.; Hwang, Sun; Mintz, Jim; Post, Robert M.

    Introduction: This study was undertaken to evaluate the prevalence rate of anxiety comorbidity in bipolar subjects with and without alcohol use disorders (AUD). Methods: Bipolar men and women who entered the Stanley Foundation Bipolar Network (SFBN) underwent a Structured Clinical Interview for

  3. Nanoscale nuclei in phase change materials: Origin of different crystallization mechanisms of Ge2Sb2Te5 and AgInSbTe

    International Nuclear Information System (INIS)

    Lee, Bong-Sub; Bogle, Stephanie N.; Darmawikarta, Kristof; Abelson, John R.; Shelby, Robert M.; Retter, Charles T.; Burr, Geoffrey W.; Raoux, Simone; Bishop, Stephen G.

    2014-01-01

    Phase change memory devices are based on the rapid and reversible amorphous-to-crystalline transformations of phase change materials, such as Ge 2 Sb 2 Te 5 and AgInSbTe. Since the maximum switching speed of these devices is typically limited by crystallization speed, understanding the crystallization process is of crucial importance. While Ge 2 Sb 2 Te 5 and AgInSbTe show very different crystallization mechanisms from their melt-quenched states, the nanostructural origin of this difference has not been clearly demonstrated. Here, we show that an amorphous state includes different sizes and number of nanoscale nuclei, after thermal treatment such as melt-quenching or furnace annealing is performed. We employ fluctuation transmission electron microscopy to detect nanoscale nuclei embedded in amorphous materials, and use a pump-probe laser technique and atomic force microscopy to study the kinetics of nucleation and growth. We confirm that melt-quenched amorphous Ge 2 Sb 2 Te 5 includes considerably larger and more quenched-in nuclei than its as-deposited state, while melt-quenched AgInSbTe does not, and explain this contrast by the different ratio between quenching time and nucleation time in these materials. In addition to providing insights to the crystallization process in these technologically important devices, this study presents experimental illustrations of temperature-dependence of nucleation rate and growth speed, which was predicted by theory of phase transformation but rarely demonstrated

  4. Amorphization of metals by ion implantation and ion beam mixing

    International Nuclear Information System (INIS)

    Rauschenbach, B.; Heera, V.

    1988-01-01

    Amorphous metallic systems can be formed either by high-fluence ion implantation of glassforming species or by irradiation of layered metal systems with inert gas ions. Both techniques and experimental examples are presented. Empirical rules are discussed which predict whether a given system can be transformed into an amorphous phase. Influence of temperature, implantation dose and pre-existing crystalline metal composition on amorphization is considered. Examples are given of the implantation induced amorphous structure, recrystallization and formation of quasicrystalline structures. (author)

  5. Dynamics of hydrogen in hydrogenated amorphous silicon

    Indian Academy of Sciences (India)

    weak (strained) Si–Si bond thereby apparently enhancing the hydrogen diffusion and increasing the light-induced dangling bonds. Keywords. Hydrogenated amorphous silicon; metastable electronic states; hydrogen diffusion. PACS Nos 61.43.Dq; 66.30.-h; 71.23.Cq. 1. Introduction. Hydrogen passivation of dangling bonds ...

  6. Characterization of amorphous hydrogenated carbon films ...

    Indian Academy of Sciences (India)

    Amorphous hydrogenated carbon films (-C:H) on -type (100) silicon wafers were prepared with a middle frequency pulsed unbalanced magnetron sputtering technique (MFPUMST) at different ratios of methane–argon gases. The band characteristics, mechanical properties as well as refractive index were measured by ...

  7. Characterization of amorphous hydrogenated carbon films ...

    Indian Academy of Sciences (India)

    †Key Laboratory of Radiation and Technology of Education Ministry of China, Institute of Nuclear Science and. Technology, Sichuan University, Chengdu 610064, P. R. China. MS received 14 March 2011; revised 29 October 2011. Abstract. Amorphous hydrogenated carbon films (a-C:H) on p-type (100) silicon wafers were ...

  8. Unusual photoanisotropic alignment in amorphous azobenzene polymers

    DEFF Research Database (Denmark)

    Ramanujam, P.S.

    2015-01-01

    It is well known that irradiation of azobenzene polymer films between 490 and 530nm results in alignment of molecules perpendicular to the polarization of the incident beam. I have recently found that irradiation of amorphous azobenzene polymers with linearly polarized light at wavelengths between...

  9. Compaction of amorphous iron–boron powder

    DEFF Research Database (Denmark)

    Hendriksen, Peter Vang; Mørup, Steen; Koch, Christian

    1993-01-01

    report on attempts to compact amorphous iron–boron particles prepared by chemical reduction of Fe(II) ions in aqueous solution by NaBH4 (Ref. 2). The particles prepared in this way are pyrophoric, but can be passivated. The small particle size (10–100 nm), characteristic of this preparation technique...

  10. Trap level spectroscopy in amorphous semiconductors

    CERN Document Server

    Mikla, Victor V

    2010-01-01

    Although amorphous semiconductors have been studied for over four decades, many of their properties are not fully understood. This book discusses not only the most common spectroscopic techniques but also describes their advantages and disadvantages.Provides information on the most used spectroscopic techniquesDiscusses the advantages and disadvantages of each technique

  11. Film adhesion in amorphous silicon solar cells

    Indian Academy of Sciences (India)

    TECS

    Abstract. A major issue encountered during fabrication of triple junction a-Si solar cells on polyimide sub- strates is the adhesion of the solar cell thin films to the substrates. Here, we present our study of film adhesion in amorphous silicon solar cells made on different polyimide substrates (Kapton VN, Upilex-S and ...

  12. Structural morphology of amorphous conducting carbon film

    Indian Academy of Sciences (India)

    Amorphous conducting carbon films deposited over quartz substrates were analysed using X-ray diffraction and AFM technique. X-ray diffraction data reveal disorder and roughness in the plane of graphene sheet as compared to that of graphite. This roughness increases with decrease in preparation temperature. The AFM ...

  13. Film adhesion in amorphous silicon solar cells

    Indian Academy of Sciences (India)

    A major issue encountered during fabrication of triple junction -Si solar cells on polyimide substrates is the adhesion of the solar cell thin films to the substrates. Here, we present our study of film adhesion in amorphous silicon solar cells made on different polyimide substrates (Kapton VN, Upilex-S and Gouldflex), and the ...

  14. Characterization of amorphous and nanocrystalline carbon films

    International Nuclear Information System (INIS)

    Chu, Paul K.; Li Liuhe

    2006-01-01

    Amorphous and nanocrystalline carbon films possess special chemical and physical properties such as high chemical inertness, diamond-like properties, and favorable tribological proprieties. The materials usually consist of graphite and diamond microstructures and thus possess properties that lie between the two. Amorphous and nanocrystalline carbon films can exist in different kinds of matrices and are usually doped with a large amount of hydrogen. Thus, carbon films can be classified as polymer-like, diamond-like, or graphite-like based on the main binding framework. In order to characterize the structure, either direct bonding characterization methods or the indirect bonding characterization methods are employed. Examples of techniques utilized to identify the chemical bonds and microstructure of amorphous and nanocrystalline carbon films include optical characterization methods such as Raman spectroscopy, Ultra-violet (UV) Raman spectroscopy, and infrared spectroscopy, electron spectroscopic and microscopic methods such as scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy, transmission electron microscopy, and electron energy loss spectroscopy, surface morphology characterization techniques such as scanning probe microscopy (SPM) as well as other characterization methods such as X-ray reflectivity and nuclear magnetic resonance. In this review, the structures of various types of amorphous carbon films and common characterization techniques are described

  15. Dynamics of hydrogen in hydrogenated amorphous silicon

    Indian Academy of Sciences (India)

    c0, c being the instantaneous concentration at a local point and c0, the average concentration of hydrogen in the hydrogenated amorphous silicon. If the system is both incompressible and isotropic, the change in Helmholtz free energy due to fluctuations in the local concentration of hydrogen is given as. 122. Pramana – J.

  16. Radiative recombination of excitons in amorphous semiconductors

    International Nuclear Information System (INIS)

    Singh, Jai

    2005-01-01

    A theory for calculating the radiative lifetime of excitons in amorphous semiconductors is presented. Four possibilities of excitonic radiative recombination are considered and the corresponding rates are derived at thermal equilibrium. The radiative lifetime is calculated from the inverse of the maximum rate for all the four possibilities. Results agree very well with experiments

  17. Neutron diffraction studies of amorphous solids

    International Nuclear Information System (INIS)

    Wright, A.C.

    1983-01-01

    A brief survey is presented of the role of neutron diffraction in structural studies of amorphous solids. The inherent limitations of the diffraction technique are discussed, together with modern instrumentation and methods for separating individual component correlation functions. An introduction is given to the use of modelling and the extraction of structural parameters from experimental data. (author)

  18. Amorphous calcium carbonate particles form coral skeletons

    Science.gov (United States)

    Mass, Tali; Giuffre, Anthony J.; Sun, Chang-Yu; Stifler, Cayla A.; Frazier, Matthew J.; Neder, Maayan; Tamura, Nobumichi; Stan, Camelia V.; Marcus, Matthew A.; Gilbert, Pupa U. P. A.

    2017-09-01

    Do corals form their skeletons by precipitation from solution or by attachment of amorphous precursor particles as observed in other minerals and biominerals? The classical model assumes precipitation in contrast with observed “vital effects,” that is, deviations from elemental and isotopic compositions at thermodynamic equilibrium. Here, we show direct spectromicroscopy evidence in Stylophora pistillata corals that two amorphous precursors exist, one hydrated and one anhydrous amorphous calcium carbonate (ACC); that these are formed in the tissue as 400-nm particles; and that they attach to the surface of coral skeletons, remain amorphous for hours, and finally, crystallize into aragonite (CaCO3). We show in both coral and synthetic aragonite spherulites that crystal growth by attachment of ACC particles is more than 100 times faster than ion-by-ion growth from solution. Fast growth provides a distinct physiological advantage to corals in the rigors of the reef, a crowded and fiercely competitive ecosystem. Corals are affected by warming-induced bleaching and postmortem dissolution, but the finding here that ACC particles are formed inside tissue may make coral skeleton formation less susceptible to ocean acidification than previously assumed. If this is how other corals form their skeletons, perhaps this is how a few corals survived past CO2 increases, such as the Paleocene-Eocene Thermal Maximum that occurred 56 Mya.

  19. Amorphous track models: A numerical comparison study

    DEFF Research Database (Denmark)

    Greilich, Steffen; Grzanka, L.; Bassler, N.

    2010-01-01

    We present an open-source code library for amorphous track modelling which is suppose to faciliate the application and numerical comparability as well as serve as a frame-work for the implementation of new models. We show an example of using the library indicating the choice of submodels has a si...

  20. The Electronic Structure of Amorphous Carbon Nanodots.

    Science.gov (United States)

    Margraf, Johannes T; Strauss, Volker; Guldi, Dirk M; Clark, Timothy

    2015-06-18

    We have studied hydrogen-passivated amorphous carbon nanostructures with semiempirical molecular orbital theory in order to provide an understanding of the factors that affect their electronic properties. Amorphous structures were first constructed using periodic calculations in a melt/quench protocol. Pure periodic amorphous carbon structures and their counterparts doped with nitrogen and/or oxygen feature large electronic band gaps. Surprisingly, descriptors such as the elemental composition and the number of sp(3)-atoms only influence the electronic structure weakly. Instead, the exact topology of the sp(2)-network in terms of effective conjugation defines the band gap. Amorphous carbon nanodots of different structures and sizes were cut out of the periodic structures. Our calculations predict the occurrence of localized electronic surface states, which give rise to interesting effects such as amphoteric reactivity and predicted optical band gaps in the near-UV/visible range. Optical and electronic gaps display a dependence on particle size similar to that of inorganic colloidal quantum dots.

  1. Plasma deposition of amorphous metal alloys

    Science.gov (United States)

    Hays, Auda K.

    1986-01-01

    Amorphous metal alloy coatings are plasma-deposited by dissociation of vapors of organometallic compounds and metalloid hydrides in the presence of a reducing gas, using a glow discharge. Tetracarbonylnickel, phosphine, and hydrogen constitute a typical reaction mixture of the invention, yielding a NiPC alloy.

  2. Transtorno afetivo bipolar: um enfoque transcultural Transcultural aspects of bipolar disorder

    Directory of Open Access Journals (Sweden)

    Marsal Sanches

    2004-10-01

    Full Text Available Considerando-se que existem diferenças importantes na maneira como as emoções são vivenciadas e expressas em diferentes culturas, a apresentação e o manejo do transtorno afetivo bipolar sofrem influência de fatores culturais. O presente artigo realiza uma breve revisão da evidência referente aos aspectos transculturais do transtorno bipolar.Cultural variations in the expression of emotions have been described. Consequently, there are cross-cultural influences on the diagnosis and management of bipolar disorder. This article provides a review of the evidence regarding the main aspects of transcultural psychiatry and bipolar disorder.

  3. Influence of Si and N additions on structure and phase stability of Ge2Sb2Te5 thin films

    International Nuclear Information System (INIS)

    Koelpin, Helmut; Music, Denis; Mykhaylonka, Ruslan; Schneider, Jochen M; Laptyeva, Galyna; Ghadimi, Reza; Richter, Silvia; Mayer, Joachim; Merget, Florian

    2009-01-01

    The influence of Si and N in Ge 2 Sb 2 Te 5 (space group Fm3-barm) on structure and phase stability thereof was studied experimentally by thin film growth and characterization as well as theoretically by ab initio calculations. It was found that Si and N most probably accumulate in the amorphous matrix embedding Ge 2 Sb 2 Te 5 grains. The incorporation of Si and N in these samples causes an increase of the crystallization temperature and the formation of finer grains. N is more efficient in increasing the crystallization temperature and in reducing the grain size than Si which can be understood based on the bonding analysis. The incorporation of both Si and N in Ge 2 Sb 2 Te 5 is energetically unfavourable, leading to finer grains and larger crystallization temperatures. While in the case of Si additions no significant changes in bonding are observed, N additions appear to enable the formation of strong Te-N bonds in the amorphous matrix, which are shown to be almost twice as strong as the strongest bonds in unalloyed Ge 2 Sb 2 Te 5 .

  4. Discovery of an internal-friction peak in the metallic glass Nb3Ge

    International Nuclear Information System (INIS)

    Berry, B.S.; Pritchet, W.C.; Tsuei, C.C.

    1978-01-01

    A well-defined internal-friction peak has been observed near 260 K in amorphous rf-sputtered films of Nb 3 Ge, studied at audio frequencies by a vibrating-reed technique. The characteristics of the peak are consistent with a stress-induced ordering mechanism involving a presently unidentified center which undergoes reorientation by an atomic jump with a sharply defined activation energy of 0.52 eV. The peak appears to be the first example of its type found in a metallic glass

  5. Si and Ge nanostructures epitaxy on a crystalline insulating LaAlO{sub 3}(001) substrate

    Energy Technology Data Exchange (ETDEWEB)

    Bischoff, Jean-Luc; Mortada, Hussein; Dentel, Didier; Derivaz, Mickael [Institut de Science des Materiaux de Mulhouse (IS2M), LRC 7228 CNRS-UHA, Universite de Haute Alsace, Mulhouse (France); Ben Azzouz, Chiraz; Akremi, Abdelwahab; Chefi, Chaabanne [Equipe Surface et Interface (ESI) - Faculte des Sciences, Bizerte (Tunisia); Morales, Francisco Miguel; Herrera, Miriam; Manuel, Jose Manuel; Garcia, Rafael [Department of Materials Science, Metallurgical Engineering and Inorganic Chemistry, Cadiz University (Spain); Diani, Mustapha [Equipe de Recherche en Mecanique, Materiaux et Metallurgie, FST, Tanger (Morocco)

    2012-04-15

    We present a comparative structural study of the growth of Si and Ge deposited by molecular beam epitaxy (MBE) on a c(2 x 2) reconstructed LaAlO{sub 3}(001) substrate. Our findings are based on complementary experimental techniques such as in situ X-ray photoelectron spectroscopy (XPS), reflection high-energy electron diffraction (RHEED), low energy electron diffraction (LEED) and ex situ atomic force microscopy (AFM) and high resolution transmission electron microscopy (HRTEM). While the layers are amorphous and wet uniformly the substrate in a low deposition temperature range, above 500 C both Si and Ge growths proceed in a Volmer-Weber (VW) mode leading to the formation of nanocrystals (NCs). The islands are found to be composed of pure Si and Ge and to have abrupt interfaces with the substrate. Both semiconductors (SCs) crystallize in their own diamond structure leading to relaxed NCs. No facets could be observed on the crystalline islands. An epitaxial relationship is established for which the (001) planes of Si and Ge are parallel to the LaAlO{sub 3}(001) surface but are rotated by 45 around the [001] growth axis. The Ge lattice undergoes a second rotation of 6 with respect to the (001) growth axis. This 6 tilt is an original mechanism to partially compensate the strain in the Ge islands induced by the large misfit. Whereas a unique epitaxial relationship is pointed out for Si NCs, many Ge NCs are randomly orientated on the surface. This is interpreted by the fact that the Ge islands are less anchored to the substrate due to a large misfit and to the fact that the Ge-O bonds are weaker than the Si-O ones. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. BIPOLAR DISORDER AND METABOLIC SYNDROME: COMORBIDITY OR SIDE EFFECTS OF TREATMENT OF BIPOLAR DISORDER

    OpenAIRE

    Babić, Dragan; Maslov, Boris; Nikolić, Katica; Martinac, Marko; Uzun, Suzana; Kozumplik, Oliver

    2010-01-01

    Objective: There is evidence that people with mental disorders are more likely to suffer from metabolic syndrome. In the last decades there has been an increase in interest for researching metabolic syndrome in psychiatric patients and plenty of evidence about their association. However, investigations on the prevalence of metabolic syndrome in patients with bipolar disorder are still surprisingly rare. The aim of this paper is to analyze comorbidity of bipolar disorder and metabolic syndrome...

  7. Electrical properties and degradation behavior of hydrogenated amorphous Si alloys for solar cells

    Science.gov (United States)

    Krühler, W.; Kusian, W.; Karg, F.; Pfleiderer, H.

    1986-12-01

    The electrical properties and the degradation behavior of hydrogenated amorphous silicon alloys (a-Si1- x A x : H, with A=C, Ge, B, P) in designs of pin, pip, nin, and MOS structures are investigated by measuring the dark and light I(V) characteristics and the spectral response as well as the space-charge-limited current (SCLC), the time of flight (TOF) of carriers and the field effect (FE). These investigations give an overview of our recent work combined with new results emphasizing the physics of the a-Si:H pin solar cells. We discuss the stabilizing influence on the degradation behavior achieved by profiling the i layers of the pin solar cells with P and B. Two kinds of pin solar cells, namely glass/SnO2/p(C)in/metal and glass/metal/pin/ITO, are investigated and an explanation of their different spectral response behavior is given. SCLC measurements lead to the conclusion that trapping is also involved in the degradation mechanism, as is recombination. TOF experiments on a-Si1- x Ge x : H pin diodes indicate that the incorporation of Ge widens the tail-state distribution below the conduction band. FE measurements showed densities of gap states of about 5×l016cm-3eV-1.

  8. Crystallization of biogenic hydrous amorphous silica

    Science.gov (United States)

    Kyono, A.; Yokooji, M.; Chiba, T.; Tamura, T.; Tuji, A.

    2017-12-01

    Diatom, Nitzschia cf. frustulum, collected from Lake Yogo, Siga prefecture, Japan was cultured in laboratory. Organic components of the diatom cell were removed by washing with acetone and sodium hypochlorite. The remaining frustules were studied by SEM-EDX, FTIR spectroscopy, and synchrotron X-ray diffraction. The results showed that the spindle-shaped morphology of diatom frustule was composed of hydrous amorphous silica. Pressure induced phase transformation of the diatom frustule was investigated by in situ Raman spectroscopic analysis. With exposure to 0.3 GPa at 100 oC, Raman band corresponding to quartz occurred at ν = 465 cm-1. In addition, Raman bands known as a characteristic Raman pattern of moganite was also observed at 501 cm-1. From the integral ratio of Raman bands, the moganite content in the probed area was estimated to be approximately 50 wt%. With the pressure and temperature effect, the initial morphology of diatom frustule was completely lost and totally changed to a characteristic spherical particle with a diameter of about 2 mm. With keeping the compression of 5.7 GPa at 100 oC, a Raman band assignable to coesite appeared at 538 cm-1. That is, with the compression and heating, the hydrous amorphous silica can be readily crystallized into quartz, moganite, and coesite. The first-principles calculations revealed that a disiloxane molecule stabilized in a trans configuration is twisted 60o and changed into the cis configuration with a close approach of water molecule. It is therefore a reasonable assumption that during crystallization of hydrous amorphous silica, the Si-O-Si bridging unit with the cis configuration would survive as a structural defect and then crystallized into moganite by keeping the geometry. This hypothesis is adaptable to the phase transformation from hydrous amorphous silica to coesite as well, because coesite has the four-membered rings and easily formed from the hydrous amorphous silica under high pressure and high

  9. Observation of channeling for 6500 GeV/c protons in the crystal assisted collimation setup for LHC

    Directory of Open Access Journals (Sweden)

    W. Scandale

    2016-07-01

    Full Text Available Two high-accuracy goniometers equipped with two bent silicon crystals were installed in the betatron cleaning insertion of the CERN Large Hadron Collider (LHC during its long shutdown. First beam tests were recently performed at the LHC with 450 GeV/c and 6500 GeV/c stored proton beams to investigate the feasibility of beam halo collimation assisted by bent crystals. For the first time channeling of 6500 GeV/c protons was observed in a particle accelerator. A strong reduction of beam losses due to nuclear inelastic interactions in the aligned crystal in comparison with its amorphous orientation was detected. The loss reduction value was about 24. Thus, the results show that deflection of particles by a bent crystal due to channeling is effective for this record particle energy.

  10. Peierls distortion mediated reversible phase transition in GeTe under pressure.

    Science.gov (United States)

    Sun, Zhimei; Zhou, Jian; Mao, Ho-Kwang; Ahuja, Rajeev

    2012-04-17

    With the advent of big synchrotron facilities around the world, pressure is now routinely placed to design a new material or manipulate the properties of materials. In GeTe, an important phase-change material that utilizes the property contrast between the crystalline and amorphous states for data storage, we observed a reversible phase transition of rhombohedral ↔ rocksalt ↔ orthorhombic ↔ monoclinic coupled with a semiconductor ↔ metal interconversion under pressure on the basis of ab initio molecular dynamics simulations. This interesting reversible phase transition under pressure is believed to be mediated by Peierls distortion in GeTe. Our results suggest a unique way to understand the reversible phase transition and hence the resistance switching that is crucial to the applications of phase-change materials in nonvolatile memory. The present finding can also be expanded to other IV-VI semiconductors.

  11. First-Principles Prediction of Densities of Amorphous Materials: The Case of Amorphous Silicon

    Science.gov (United States)

    Furukawa, Yoritaka; Matsushita, Yu-ichiro

    2018-02-01

    A novel approach to predict the atomic densities of amorphous materials is explored on the basis of Car-Parrinello molecular dynamics (CPMD) in density functional theory. Despite the determination of the atomic density of matter being crucial in understanding its physical properties, no first-principles method has ever been proposed for amorphous materials until now. We have extended the conventional method for crystalline materials in a natural manner and pointed out the importance of the canonical ensemble of the total energy in the determination of the atomic densities of amorphous materials. To take into account the canonical distribution of the total energy, we generate multiple amorphous structures with several different volumes by CPMD simulations and average the total energies at each volume. The density is then determined as the one that minimizes the averaged total energy. In this study, this approach is implemented for amorphous silicon (a-Si) to demonstrate its validity, and we have determined the density of a-Si to be 4.1% lower and its bulk modulus to be 28 GPa smaller than those of the crystal, which are in good agreement with experiments. We have also confirmed that generating samples through classical molecular dynamics simulations produces a comparable result. The findings suggest that the presented method is applicable to other amorphous systems, including those for which experimental knowledge is lacking.

  12. Unblending Borderline Personality and Bipolar Disorders.

    Science.gov (United States)

    di Giacomo, Ester; Aspesi, Flora; Fotiadou, Maria; Arntz, Arnoud; Aguglia, Eugenio; Barone, Lavinia; Bellino, Silvio; Carpiniello, Bernardo; Colmegna, Fabrizia; Lazzari, Marina; Lorettu, Liliana; Pinna, Federica; Sicaro, Aldo; Signorelli, Maria Salvina; Clerici, Massimo

    2017-08-01

    Borderline Personality (BPD) and Bipolar (BP) disorders stimulate an academic debate between their distinction and the inclusion of Borderline in the Bipolar spectrum. Opponents to this inclusion attribute the important differences and possible diagnostic incomprehension to overlapping symptoms. We tested 248 Borderline and 113 Bipolar patients, consecutively admitted to the Psychiatric Unit, through DSM-IV Axis I and II Disorders (SCID-I/II), Hamilton Depression Rating Scale (HAM-D), Hamilton Anxiety Rating Scale (HAM-A), Young Mania Rating Scale (YMRS) and Borderline Personality Disorder Severity Index-IV (BPDSI-IV). All the tests statistically discriminated the disorders (p Borderline patients with manic features offer a privileged point of view for a deeper analysis. This allows for the possibility of a more precise examination of the nature and load of each symptom. Borderline Personality and Bipolar Disorders can be distinguished with high precision using common and time-sparing tests. The importance of discriminating these clinical features may benefit from this evidence. Copyright © 2017. Published by Elsevier Ltd.

  13. Bipolar disorder: Evidence for a major locus

    Energy Technology Data Exchange (ETDEWEB)

    Spence, M.A.; Flodman, P.L. [Univ. of California, Irvine, CA (United States); Sadovnick, A.D.; Ameli, H. [Univ. of British Columbia, Vancouver (Canada)] [and others

    1995-10-09

    Complex segregation analyses were conducted on families of bipolar I and bipolar II probands to delineate the mode of inheritance. The probands were ascertained from consecutive referrals to the Mood Disorder Service, University Hospital, University of British Columbia and diagnosed by DSM-III-R and Research Diagnostic Criteria. Data were available on over 1,500 first-degree relatives of the 186 Caucasian probands. The purpose of the analyses was to determine if, after correcting for age and birth cohort, there was evidence for a single major locus. Five models were fit to the data using the statistical package SAGE: (1) dominant, (2) recessive, (3) arbitrary mendelian inheritance, (4) environmental, and (5) no major effects. A single dominant, mendelian major locus was the best fitting of these models for the sample of bipolar I and II probands when only bipolar relatives were defined as affected (polygenic inheritance could not be tested). Adding recurrent major depression to the diagnosis {open_quotes}affected{close_quotes} for relatives reduced the evidence for a major locus effect. Our findings support the undertaking of linkage studies and are consistent with the analyses of the National Institutes of Mental Health (NIMH) Collaborative Study data by Rice et al. and Blangero and Elston. 39 refs., 4 tabs.

  14. Comorbidity of bipolar disorder and eating disorders.

    Science.gov (United States)

    Álvarez Ruiz, Eva M; Gutiérrez-Rojas, Luis

    2015-01-01

    The comorbidity of bipolar disorder and eating disorders has not been studied in depth. In addition, clinical implications involved in the appearance of both disorders are very important. A systematic literature review of MEDLINE published up to September 2013 was performed, analyzing all the articles that studied the comorbidity of both conditions (bipolar disorder and eating disorders) and others research that studied the efficacy of pharmacological treatment and psychotherapy to improve these illnesses. In this review we found a high comorbidity of bipolar disorder and eating disorders, especially of bulimia nervosa and binge eating disorder. Studies show that lithium and topiramate are 2 of the more effective pharmacological agents in the treatment of both disorders. There are a lot of studies that show evidence of comorbidity of bipolar disorder and eating disorders. However, further research is needed on assessment and treatment when these conditions co-exist, as well as study into the biopsychological aspects to determine the comorbid aetiology. Copyright © 2014 SEP y SEPB. Published by Elsevier España. All rights reserved.

  15. Radiation Damage In Advanced Bipolar Transistors

    Science.gov (United States)

    Zoutendyk, John A.; Goben, Charles A.; Berndt, Dale F.

    1989-01-01

    Report describes measurements of common-emitter current gains (hFE) of advanced bipolar silicon transistors before, during, and after irradiation with 275-MeV bromine ions, 2.5-MeV electrons, and conductivity rays from cobalt-60 atoms.

  16. Facial affect recognition deficits in bipolar disorder.

    Science.gov (United States)

    Getz, Glen E; Shear, Paula K; Strakowski, Stephen M

    2003-05-01

    Patients diagnosed with bipolar disorder (BPD), by definition, have problems with emotional regulation. However, it remains uncertain whether these patients are also deficient at processing other people's emotions, particularly while manic. The present study examined the ability of 25 manic bipolar patients and 25 healthy participants on tasks of facial recognition and facial affect recognition at three different presentation durations: 500 ms, 750 ms, and 1000 ms. The groups did not differ in terms of age, education, sex, ethnicity, or estimated IQ. The groups did not differ significantly on either a novel computerized facial recognition task or the Benton Facial Recognition Test. In contrast, the bipolar group performed significantly more poorly than did the comparison group on a novel facial affect labeling task. Although the patient group had slower reaction times on all 3 computerized tasks, the presentation duration did not have an effect on performance in the patients. This study suggests that patients with bipolar disorder are able to recognize faces, but have difficulty processing facial affective cues.

  17. Heart rate variability in bipolar disorder

    DEFF Research Database (Denmark)

    Faurholt-Jepsen, Maria; Kessing, Lars Vedel; Munkholm, Klaus

    2017-01-01

    Background Heart rate variability (HRV) has been suggested reduced in bipolar disorder (BD) compared with healthy individuals (HC). This meta-analysis investigated: HRV differences in BD compared with HC, major depressive disorder or schizophrenia; HRV differences between affective states; HRV...

  18. Bipolarity and Ambivalence in Landscape Architecture

    NARCIS (Netherlands)

    Koh, J.

    2010-01-01

    Our discipline of landscape architecture contains bipolarity, not only in terms of landscape and architecture but also because the idea of landscape is both aesthetic and scientific. Furthermore, within landscape architecture there is a gap between design (as implied by architecture) and planning

  19. Atomic scale characterization of ion-induced amorphization of GaAs and InAs using PAC spectroscopy

    International Nuclear Information System (INIS)

    Dogra, R.; Byrne, A.P.; Ridgway, M.C.

    2005-01-01

    Single crystals of GaAs (100) and InAs (100) were implanted with 1-7 MeV 74 Ge ions over a wide dose range at liquid nitrogen temperature. The implanted substrates were investigated with respect to the damage production by means of perturbed angular correlation spectroscopy based upon hyperfine interactions of nuclear electromagnetic moments of probe nuclei with extra-nuclear fields. The perturbed angular correlation measurements were performed at room temperature utilizing the 111 In/Cd radioisotope probe nuclei. The crystalline, disordered and amorphous probe environments were identified from the measurements. The defect production is described within the framework of different amorphization models. (author). 6 refs., 2 figs

  20. SiGe nano-heteroepitaxy on Si and SiGe nano-pillars.

    Science.gov (United States)

    Mastari, Marouane; Charles, Matthew; Bogumilowicz, Yann; Thai, Quang Minh; Pimenta Barros, Patricia; Argoud, Maxime; Papon, Anne-Marie; Gergaud, Patrice; Landru, Didier; Kim, Youngpil; Hartmann, Jean Michel

    2018-04-12

    In this paper, SiGe nano-heteroepitaxy on Si and SiGe nano-pillars was investigated in a 300 mm industrial Reduced Pressure-Chemical Vapour Deposition tool. An integration scheme based on diblock copolymer patterning was used to fabricate nanometer-sized templates for the epitaxy of Si and SiGe nano-pillars. Results showed highly selective and uniform processes for the epitaxial growth of Si and SiGe nano-pillars. 200 nm thick SiGe layers were grown on Si and SiGe nano-pillars and characterized by AFM, XRD and TEM. Smooth SiGe surfaces and full strain relaxation were obtained in the 650-700°C range for 2D SiGe layers grown either on Si or SiGe nano-pillars. © 2018 IOP Publishing Ltd.

  1. Structure and magnetic properties of Fe2CoGe synthesized by ball-milling

    International Nuclear Information System (INIS)

    Ren, Z.; Li, S.T.; Luo, H.Z.

    2010-01-01

    A Heusler alloy Fe 2 CoGe has been synthesized by the ball-milling method. Its structure and magnetic properties have been studied. The results suggest that ball-milling can be a possible way to produce new Heusler alloys. Both X-ray diffraction and DTA measurement evidenced the formation of a partly amorphous phase after milling for 25 h. It is found that highly ordered Fe 2 CoGe can be obtained by annealing the as-milled powder at 1073 K, while a disordered A2 phase is resulted by annealing at 773 K. The magnetic properties of Fe 2 CoGe are not very sensitive to the atomic disorder. Electronic structure calculation suggests a ferromagnetic ground state in highly ordered Fe 2 CoGe and the total spin moment is 5.03μ B /f.u., which agrees well with the experimental value of 5.06μ B for the sample annealed at 1073 K. It is also found that the atomic disorder does not strongly change the ferromagnetic coupling between Fe and Co moments and also the general structure of the DOS. So the total spin moment only slightly increases when atomic disorder occurs.

  2. Far-infrared study of superconducting MoGe thin films

    Science.gov (United States)

    Tashiro, H.; Graybeal, J. M.; Tanner, D. B.; Carr, G. L.

    2003-03-01

    Amorphous MoGe serves as a model system for studying the interplay between superconductivity and disorder [Phys. Rev. B 29, 4167 (1984)]. Thin films of α-MoGe, prepared by UHV co-sputtering onto sapphire substrates (with an α-Ge buffer layer), show progressively reduced T_c's as the thickness is decreased below 30 nm and the sheet resistance exceeds 100 Ω/sq. This suppression has been explained in terms of electron localization effects and reduced screening (i.e., an increase in μ^*, the renormalized Coulomb interaction parameter). We have measured the far-infrared transmission and reflection for a set of α-MoGe films to understand more fully this weakened superconducting state. Our results show the presence of an energy gap consistent with BCS theory and 2Δ/kTc near the BCS weak coupling limit of 3.5. We report a detailed analysis using the Mattis-Bardeen expressions for the optical conductivity, and possible deviations from these expressions, due to the localization, will be discussed. Funded by DOE contracts DE-FG02-02ER45984 at UF and DE-AC02-98CH10886 at BNL.

  3. Electrical and Optical Properties of GeSi−:H Thin Films Prepared by Thermal Evaporation Method

    Directory of Open Access Journals (Sweden)

    A. A. J. Al-Douri

    2010-01-01

    Full Text Available Thin a-GeSi1−:H films were grown successfully by fabrication of designated ingot followed by evaporation onto glass slides. A range of growth conditions, Ge contents, dopant concentration (Al and As, and substrate temperature, were employed. Stoichiometry of the thin films composition was confirmed using standard surface techniques. The structure of all films was amorphous. Film composition and deposition parameters were investigated for their bearing on film electrical and optical properties. More than one transport mechanism is indicated. It was observed that increasing substrate temperature, Ge contents, and dopant concentration lead to a decrease in the optical energy gap of those films. The role of the deposition conditions on values of the optical constants was determined. Accordingly, models of the density of states for the Ge0.5Si0.5:H thin films as pure, doped with 3.5% of Al (p-type and that doped with 3.5% As (n-type, were proposed.

  4. Mesh-shape-and-size controlled rapid-melting growth for the formation of single-crystalline (100), (110), and (111) Ge networks on insulators

    International Nuclear Information System (INIS)

    Mizushima, Ichiro; Toko, Kaoru; Ohta, Yasuharu; Sakane, Takashi; Sadoh, Taizoh; Miyao, Masanobu

    2011-01-01

    Single-crystalline-Ge (c-Ge) networks with various crystal orientations on insulators formed on Si substrates are essential for integrating high-speed and multifunctional devices onto the Si platform. c-Ge networks are realized by rapid-melting growth of mesh-patterned amorphous-Ge over large areas (500x250 μm 2 ) on (110) and (111) as well as (100) Si substrates by optimizing the shape and the size of the mesh. It is revealed that latent-heat generated at the growth front can be controlled by selecting mesh-shape-and-size, which suppresses the spontaneous nucleation. In addition, essential role of the growth-direction on preventing the rotational growth is clarified.

  5. On the nature of chemical bonding in phase change materials on the base of (GeTe)m-(Sb2Te3)n alloys

    Science.gov (United States)

    Orlov, V. G.; Sergeev, G. S.

    2017-05-01

    Despite widespread use of pseudobinary alloys (GeTe)m-(Sb2Te3)n for manufacture of optical data storage memory interpretation of very fast crystallization and amorphization processes in these phase change materials (PCM) is still under discussion. To clarify the role of electron subsystem in unusual properties of PCM and to reveal the nature of their chemical bonding electron band structure calculations using WIEN2k program code were performed for compounds GeTe, Sb2Te3, GeSb2Te4 and Ge2Sb2Te5. Parameters of bond critic points in the electron density distribution for studied compounds and some related substances were obtained and analyzed. Characteristics of bond critic points inherent to basic PCM are established. They can be used as guide parameters for searching new perspective materials.

  6. Amorphous Carbon: State of the Art - Proceedings of the 1st International Specialist Meeting on Amorphous Carbon (smac '97)

    Science.gov (United States)

    Silva, S. R. P.; Robertson, J.; Milne, W. I.; Amaratunga, G. A. J.

    1998-05-01

    The Table of Contents for the full book PDF is as follows: * Preface * GROWTH AND STRUCTURE * The Structure of Tetrahedral Amorphous Carbon * Growth of DLC Films and Related Structure and Properties * Deposition Mechanism of Diamond-Like Carbon * Relaxation of sp3 Bonds in Hydrogen Free Carbon Films During Growth * MODELLING * Correlations Between Microstructure and Electronic Properties in Amorphous Carbon Based Materials * Review of Monte Carlo Simulations of Diamondlike Amorphous Carbon: Bulk, Surface, and Interface Structural Properties * DEPOSITION * Preparation of Disordered Amorphous and Partially Ordered Nano Clustered Carbon Films by Arc Deposition: A Critical Review * Plasma Deposition of Diamond-Like Carbon in an ECR-RF Discharge * Deposition of Amorphous Hydrogenated Carbon-Nitrogen Films by PECVD Using Several Hydrocarbon / Nitrogen Containing Gas Mixtures * ELECTRONIC STRUCTURE * 'Defects' and Their Detection in a-C and a-C:H * Valence Band and Gap State Spectroscopy of Amorphous Carbon by Photoelectron Emission Techniques * Photoluminescence Spectroscopy: A Probe for Inhomogeneous Structure in Polymer-Like Amorphous Carbon * Raman Characterization of Amorphous and Nanocrystalline sp3 Bonded Structures * Ultraviolet Raman Spectroscopy of Tetrahedral Amorphous Carbon Thin Films * Excitation Energy Dependent Raman and Photoluminescence Spectra of Hydrogenated Amorphous Carbon * MECHANICAL PROPERTIES * Pulsed Laser Deposited a-C: Growth, Structure and Mechanical Properties * Mechanical Properties of Laser-Assisted Deposited Amorphous Carbon Films * Mechanical and Morphology Study on Tetrahedral Amorphous Carbon Films * Time-Dependent Changes in the Mechanical Properties of Diamond-Like Carbon Films * ELECTRONIC PROPERTIES * Electronic Transport in Amorphous Carbon * Electronic Properties of Undoped/Doped Tetrahedral Amorphous Carbon * The Inclusion of Graphitic Nanoparticles in Semiconducting Amorphous Carbon to Enhance Electronic Transport Properties

  7. Characterisation of diode-connected SiGe BiCMOS HBTs for space applications

    Science.gov (United States)

    Venter, Johan; Sinha, Saurabh; Lambrechts, Wynand

    2016-02-01

    Silicon-germanium (SiGe) bipolar complementary metal-oxide semiconductor (BiCMOS) transistors have vertical doping profiles reaching deeper into the substrate when compared to lateral CMOS transistors. Apart from benefiting from high-speed, high current gain and low-output resistance due to its vertical profile, BiCMOS technology is increasingly becoming a preferred technology for researchers to realise next-generation space-based optoelectronic applications. BiCMOS transistors have inherent radiation hardening, to an extent predictable cryogenic performance and monolithic integration potential. SiGe BiCMOS transistors and p-n junction diodes have been researched and used as a primary active component for over the last two decades. However, further research can be conducted with diode-connected heterojunction bipolar transistors (HBTs) operating at cryogenic temperatures. This work investigates these characteristics and models devices by adapting standard fabrication technology components. This work focuses on measurements of the current-voltage relationship (I-V curves) and capacitance-voltage relationships (C-V curves) of diode-connected HBTs. One configuration is proposed and measured, which is emitterbase shorted. The I-V curves are measured for various temperature points ranging from room temperature (300 K) to the temperature of liquid nitrogen (77 K). The measured datasets are used to extract a model of the formed diode operating at cryogenic temperatures and used as a standard library component in computer aided software designs. The advantage of having broad-range temperature models of SiGe transistors becomes apparent when considering implementation of application-specific integrated circuits and silicon-based infrared radiation photodetectors on a single wafer, thus shortening interconnects and lowering parasitic interference, decreasing the overall die size and improving on overall cost-effectiveness. Primary applications include space-based geothermal

  8. Self organization of FeGe/FeSi/FeGe layered structures on Ge and their electrical conduction properties

    Science.gov (United States)

    Matsukura, B.; Hiraiwa, Y.; Nakajima, T.; Narumi, K.; Sakai, S.; Sadoh, T.; Miyao, M.; Maeda, Y.

    We have investigated self organization of novel FeGe/FeSi/FeGe layered structures on Ge(111) and their electrical conduction properties. From analyses of compositional change, diffusion dynamics analyses and microstructure observations, it was revealed that the self organization of the layered structures was enhanced by spinodal decomposition which may be induced by pronounced compositional changes associating to inhomogeneous interdiffusion. The electrical conduction showed singular temperature dependence which obviously reflected natureof Kondo insulator FeSi.

  9. Photoconductivity of Si/Ge multilayer structures with Ge quantum dots pseudomorphic to the Si matrix

    International Nuclear Information System (INIS)

    Talochkin, A. B.; Chistokhin, I. B.

    2011-01-01

    Longitudinal photoconductivity spectra of Si/Ge multilayer structures with Ge quantum dots grown pseudomorphically to the Si matrix are studied. Lines of optical transitions between hole levels of quantum dots and Si electronic states are observed. This allowed us to construct a detailed energy-level diagram of electron-hole levels of the structure. It is shown that hole levels of pseudomorphic Ge quantum dots are well described by the simplest “quantum box” model using actual sizes of Ge islands. The possibility of controlling the position of the long-wavelength photosensitivity edge by varying the growth parameters of Si/Ge structures with Ge quantum dots is determined.

  10. Emerging trends in the stabilization of amorphous drugs.

    Science.gov (United States)

    Laitinen, Riikka; Löbmann, Korbinian; Strachan, Clare J; Grohganz, Holger; Rades, Thomas

    2013-08-30

    The number of active pharmaceutical substances having high therapeutic potential but low water solubility is constantly increasing, making it difficult to formulate these compounds as oral dosage forms. The solubility and dissolution rate, and thus potentially the bioavailability, of these poorly water-soluble drugs can be increased by the formation of stabilized amorphous forms. Currently, formulation as solid polymer dispersions is the preferred method to enhance drug dissolution and to stabilize the amorphous form of a drug. The purpose of this review is to highlight emerging alternative methods to amorphous polymer dispersions for stabilizing the amorphous form of drugs. First, an overview of the properties and stabilization mechanisms of amorphous forms is provided. Subsequently, formulation approaches such as the preparation of co-amorphous small-molecule mixtures and the use of mesoporous silicon and silica-based carriers are presented as potential means to increase the stability of amorphous pharmaceuticals. Copyright © 2012 Elsevier B.V. All rights reserved.

  11. Amorphous-crystalline transition in thermoelectric NbO2

    International Nuclear Information System (INIS)

    Music, Denis; Chen, Yen-Ting; Bliem, Pascal; Geyer, Richard W

    2015-01-01

    Density functional theory was employed to design enhanced amorphous NbO 2 thermoelectrics. The covalent-ionic nature of Nb–O bonding is identical in amorphous NbO 2 and its crystalline counterpart. However, the Anderson localisation occurs in amorphous NbO 2 , which may affect the transport properties. We calculate a multifold increase in the absolute Seebeck coefficient for the amorphous state. These predictions were critically appraised by measuring the Seebeck coefficient of sputtered amorphous and crystalline NbO 2 thin films with the identical short-range order. The first-order phase transition occurs at approximately 550 °C, but amorphous NbO 2 possesses enhanced transport properties at all temperatures. Amorphous NbO 2 , reaching  −173 μV K −1 , exhibits up to a 29% larger absolute Seebeck coefficient value, thereby validating the predictions. (paper)

  12. The relationship between borderline personality disorder and bipolar disorder

    Science.gov (United States)

    Zimmerman, Mark; Morgan, Theresa A.

    2013-01-01

    It is clinically important to recognize both bipolar disorder and borderline personality disorder (BPD) in patients seeking treatment for depression, and it is important to distinguish between the two. Research considering whether BPD should be considered part of a bipolar spectrum reaches differing conclusions. We reviewed the most studied question on the relationship between BPD and bipolar disorder: their diagnostic concordance. Across studies, approximately 10% of patients with BPD had bipolar I disorder and another 10% had bipolar II disorder. Likewise, approximately 20% of bipolar II patients were diagnosed with BPD, though only 10% of bipolar I patients were diagnosed with BPD. While the comorbidity rates are substantial, each disorder is nontheless diagnosed in the absence of the other in the vast majority of cases (80% to 90%). In studies examining personality disorders broadly, other personality disorders were more commonly diagnosed in bipolar patients than was BPD. Likewise, the converse is also true: other axis I disorders such as major depression, substance abuse, and post-traumatic stress disorder are also more commonly diagnosed in patients with BPD than is bipolar disorder. These findings challenge the notion that BPD is part of the bipolar spectrum. PMID:24174890

  13. Sleep study in Disruptive Mood Dysregulation Disorder and Bipolar children.

    Science.gov (United States)

    Estrada-Prat, Xavier; Álvarez-Guerrico, Ion; Bleda-Hernández, María J; Camprodon-Rosanas, Ester; Batlle-Vila, Santiago; Pujals-Altes, Elena; Nascimento-Osorio, María T; Martín-López, Luís M; Álvarez-Martínez, Enric; Pérez-Solá, Víctor; Romero-Cela, Soledad

    2017-01-01

    Decreased need for sleep has been proposed as a core symptom of mania and it has been associated with the pathogenesis of Bipolar Disorder. The emergence of Disruptive Mood Dysregulation Disorder (DMDD) as a new diagnostic has been controversial and much has been speculated about its relationship with the bipolar spectrum. REM sleep fragmentation could be a biomarker of affective disorders and it would help us to differentiate them from other disorders. Polysomnographic cross-sectional study of children with DMDD, bipolar disorder and Attention Deficit Hyperactivity Disorder (ADHD). All participants underwent a psychiatric semi-structured interview to obtain the diagnosis, comorbidities and primary sleep disorders. DMDD’s sample was performed following DSM5 criteria. Perform polysomnography in a sample of bipolar, DMDD and ADHD children and compare their profiles to provide more evidence about the differences or similarities between bipolar disorder and DMDD. Bipolar group had the highest REM density values while ADHD had the lowest. REM density was not statiscally different between bipolar phenotypes. REM density was associated with antidepressant treatment, episodes of REM and their interaction. REM latency was associated with antipsychotic treatment and school performance. Bipolar patients had higher scores on the depression scale than DMDD and ADHD groups. No significant differences between the two compared affective disorders were found. However there were differences in REM density between bipolar and ADHD groups. REM sleep study could provide a new theoretical framework to better understand the pathogenesis of pediatric bipolar disorder.

  14. Effect of Ge Content on the Formation of Ge Nanoclusters in Magnetron-Sputtered GeZrOx-Based Structures

    OpenAIRE

    Khomenkova, L.; Lehninger, D.; Kondratenko, O.; Ponomaryov, S.; Gudymenko, O.; Tsybrii, Z.; Yukhymchuk, V.; Kladko, V.; von Borany, J.; Heitmann, J.

    2017-01-01

    Ge-rich ZrO2 films, fabricated by confocal RF magnetron sputtering of pure Ge and ZrO2 targets in Ar plasma, were studied by multi-angle laser ellipsometry, Raman scattering, Auger electron spectroscopy, Fourier transform infrared spectroscopy, and X-ray diffraction for varied deposition conditions and annealing treatments. It was found that as-deposited films are homogeneous for all Ge contents, thermal treatment stimulated a phase separation and a formation of crystalline Ge and ZrO2. The ?...

  15. Determination of boron in amorphous alloys

    Energy Technology Data Exchange (ETDEWEB)

    Grazhulene, S.S.; Grossman, O.V.; Kuntscher, K.K.; Malygina, L.I.; Muller, E.N.; Telegin, G.F.

    1985-10-01

    In the determination of boron in amorphous alloys containingFe, Co, B, Si, Ni, and P having unusal magnetic and electrical properties, precise analysis and rapid analysis are necessary. To improve the metrological properties of the existing procedure, to find a rapid determination of boron in amorphous alloys, and to verify the accuracy of the results, in the present work the optimization of the photometric determination after extraction of the BF/sup -//sub 4/ ion pair with methylene blue has been studied, and a boron determination by flame photometry using selective methylation has been developed. The determination of boron by the flame photometric and spectrophotometric methods is shown. When a highly precise determination is needed, the spectrophotometric procedure can be used. This procedure is distinguished by its labor intensity and duration. When the need for reproducibility is less severe, the rapid flame photometric procedure is best.

  16. Wear Resistant Amorphous and Nanocomposite Coatings

    Energy Technology Data Exchange (ETDEWEB)

    Racek, O

    2008-03-26

    Glass forming materials (critical cooling rate <10{sup 4}K.s{sup -1}) are promising for their high corrosion and wear resistance. During rapid cooling, the materials form an amorphous structure that transforms to nanocrystalline during a process of devitrification. High hardness (HV 1690) can be achieved through a controlled crystallization. Thermal spray process has been used to apply coatings, which preserves the amorphous/nanocomposite structure due to a high cooling rate of the feedstock particles during the impact on a substrate. Wear properties have been studied with respect to process conditions and feedstock material properties. Application specific properties such as sliding wear resistance have been correlated with laboratory tests based on instrumented indentation and scratch tests.

  17. Annealing behavior of high permeability amorphous alloys

    International Nuclear Information System (INIS)

    Rabenberg, L.

    1980-06-01

    Effects of low temperature annealing on the magnetic properties of the amorphous alloy Co 71 4 Fe 4 6 Si 9 6 B 14 4 were investigated. Annealing this alloy below 400 0 C results in magnetic hardening; annealing above 400 0 C but below the crystallization temperature results in magnetic softening. Above the crystallization temperature the alloy hardens drastically and irreversibly. Conventional and high resolution transmission electron microscopy were used to show that the magnetic property changes at low temperatures occur while the alloy is truly amorphous. By imaging the magnetic microstructures, Lorentz electron microscopy has been able to detect the presence of microscopic inhomogeneities in this alloy. The low temperature annealing behavior of this alloy has been explained in terms of atomic pair ordering in the presence of the internal molecular field. Lorentz electron microscopy has been used to confirm this explanation

  18. Characterization of diamond amorphized by ion implantation

    International Nuclear Information System (INIS)

    Allen, W.R.; Lee, E.H.

    1992-01-01

    Single crystal diamond has been implanted at 1 MeV with 2 x 10 20 Ar/m 2 . Rutherford backscattering spectrometry in a channeled geometry revealed a broad amorphized region underlying a thin, partially crystalline layer. Raman spectroscopy disclosed modifications in the bonding characteristic of the appearance of non-diamond carbon. The complementary nature of the two analysis techniques is demonstrated. The Knoop hardness of the implanted diamond was reduced by implantation

  19. Metastable states in amorphous chalcogenide semiconductors

    CERN Document Server

    Mikla, Victor I

    2009-01-01

    This book addresses an interesting and technologically important class of materials, the amorphous chalcogenide semiconductors. Experimental results on the structural and electronic metastable states in Se-rich chalcogenides are presented. Special attention is paid to the states in the mobility gap and their sensitivity to various factors such as irradiation, annealing and composition. Photoinduced changes of structure and physical properties are also considered and structural transformation at photocrystallization is studied in detail. Finally, the authors discuss potential applications of th

  20. SiGe Integrated Circuit Developments for SQUID/TES Readout

    Science.gov (United States)

    Prêle, D.; Voisin, F.; Beillimaz, C.; Chen, S.; Piat, M.; Goldwurm, A.; Laurent, P.

    2018-03-01

    SiGe integrated circuits dedicated to the readout of superconducting bolometer arrays for astrophysics have been developed since more than 10 years at APC. Whether for Cosmic Microwave Background (CMB) observations with the QUBIC ground-based experiment (Aumont et al. in astro-ph.IM, 2016. arXiv:1609.04372) or for the Hot and Energetic Universe science theme with the X-IFU instrument on-board of the ATHENA space mission (Barret et al. in SPIE 9905, space telescopes & instrumentation 2016: UV to γ Ray, 2016. https://doi.org/10.1117/12.2232432), several kinds of Transition Edge Sensor (TES) (Irwin and Hilton, in ENSS (ed) Cryogenic particle detection, Springer, Berlin, 2005) arrays have been investigated. To readout such superconducting detector arrays, we use time or frequency domain multiplexers (TDM, FDM) (Prêle in JINST 10:C08015, 2016. https://doi.org/10.1088/1748-0221/10/08/C08015) with Superconducting QUantum Interference Devices (SQUID). In addition to the SQUID devices, low-noise biasing and amplification are needed. These last functions can be obtained by using BiCMOS SiGe technology in an Application Specific Integrated Circuit (ASIC). ASIC technology allows integration of highly optimised circuits specifically designed for a unique application. Moreover, we could reach very low-noise and wide band amplification using SiGe bipolar transistor either at room or cryogenic temperatures (Cressler in J Phys IV 04(C6):C6-101, 1994. https://doi.org/10.1051/jp4:1994616). This paper discusses the use of SiGe integrated circuits for SQUID/TES readout and gives an update of the last developments dedicated to the QUBIC telescope and to the X-IFU instrument. Both ASIC called SQmux128 and AwaXe are described showing the interest of such SiGe technology for SQUID multiplexer controls.

  1. The mixed-mode reliability stress of silicon-germanium heterojunction bipolar transistors

    Science.gov (United States)

    Zhu, Chendong

    The objective of the dissertation is to combine the recent Mixed-Mode reliability stress studies in silicon-germanium (SiGe) heterojunction bipolar transistors (HBTs). The thesis starts with a review of SiGe HBT fundamentals, development trends, and the conventional reliability stress paths used in industry, following which the new stress path, Mixed-Mode stress, is introduced. Chapter 2 is devoted to an in-depth discussion of damage mechanisms that includes the impact ionization effect and the self-heating effect. Chapter 3 goes onto the impact ionization effect using two-dimensional calibrated MEDICI simulations. Chapter 4 assesses the reliability of SiGe HBTs in extreme temperature environments by way of comprehensive experiments and MEDICI simulations. A comparison of the device lifetimes for reverse-EB stress and mixed-mode stress indicates different damage mechanisms govern these phenomena. The thesis concludes with a summary of the project and suggestions for future research in chapter 5. This dissertation covers the following topics: (1) Introduces a new mixed-mode stress technique: time cumulative stress (Chapter II, also published in [23] and [24]). (2) Identifies impact ionization effects in the stress damage (Chapter II, also published in [23] and [24]). (3) Investigates for the first time mixed-mode damage using TCAD simulations at both room temperature and cryogenic temperatures (Chapter III and IV, also published in [23][24][62]). (4) Analyzes for the first time impact of self-heating on mixed-mode stress response, and identifies a temperature triggered damage threshold (Chapter II, will be published in [25]). (5) Explains the geometrical scaling issues in mixed-mode stress and explores mixed-mode stress reliability scaling trends (Chapter II, will be published in [25]). (6) Assesses for the first time SiGe HBT reliability at cryogenic temperatures (Chapter VI, also published in [62]).

  2. Electrical determination of the bandgap energies of the emitter and base regions of bipolar junction transistors

    Science.gov (United States)

    Mimila-Arroyo, J.

    2016-10-01

    A pure electrical method is presented to extract emitter and base bandgaps of a bipolar junction transistor (BJT) at the locations where the minority carrier injection takes place. It is based on the simultaneous measurement of the collector and base currents as a function of the emitter-base forward bias (Gummer plot) and the corresponding current gain. From the obtained saturation currents as a function of temperature, we extract the bandgap energies. The accuracy of the method is demonstrated for InGaP-GaAs, Si, and Ge commercial devices. For InGaP-GaAs transistors, the results can be understood if the emitter-base heterojunction is not an abrupt but a gradual one. The presented method is a reliable tool that can aid in the development of new compound semiconductor based BJTs whose bandgap energies are highly sensitive to their composition.

  3. Properties of laser-crystallized polycrystalline SiGe thin films

    Energy Technology Data Exchange (ETDEWEB)

    Weizman, Moshe

    2008-06-06

    In this thesis, structural, electrical, and optical properties of laser-crystallized polycrystalline Si{sub 1-x}Ge{sub x} thin films with 0amorphous Si{sub 1-x}Ge{sub x} thin films with 0.3Amorphous SiGe samples that are exposed to a single laser pulse exhibit a ripple structure that evolves into a hillock structure when the samples are irradiated with additional laser pulses. - It is maintained that the main mechanism behind the structure formation is an instability of the propagating solid-liquid interface during solidification. - The study of defects with electron spin resonance showed that laser-crystallized poly-Si{sub 1-x}Ge{sub x} thin films with 0Ge content. The defect density for solid-phase crystallized SiGe films was lower and amounted to N{sub s}=7 x 10{sup 17} cm{sup -3}. - Germanium-rich laser-crystallized poly-SiGe thin films exhibited mostly a broad atypical electric dipole spin resonance (EDSR) signal that was accompanied by a nearly temperature-independent electrical conductivity in the range 20-100 K. - Most likely, the origin of the grain boundary conductance is due to dangling-bond defects and not impurities. Metallic-like conductance occurs when the dangling-bond defect density is above a critical value of about N{sub C} {approx} 10{sup 18} cm{sup -3}. - Laser crystallized poly-Si{sub 1-x}Ge{sub x} thin films with x{>=}0.5 exhibit optical absorption behavior that is characteristic for disordered SiGe, implying that the absorption occurs primarily at the grain boundaries. A sub-band-gap absorption peak was found for

  4. Fluctuation microscopy analysis of amorphous silicon models

    International Nuclear Information System (INIS)

    Gibson, J.M.; Treacy, M.M.J.

    2017-01-01

    Highlights: • Studied competing computer models for amorphous silicon and simulated fluctuation microscopy data. • Show that only paracrystalline/random network composite can fit published data. • Specifically show that pure random network or random network with void models do not fit available data. • Identify a new means to measure volume fraction of ordered material. • Identify unreported limitations of the Debye model for simulating fluctuation microscopy data. - Abstract: Using computer-generated models we discuss the use of fluctuation electron microscopy (FEM) to identify the structure of amorphous silicon. We show that a combination of variable resolution FEM to measure the correlation length, with correlograph analysis to obtain the structural motif, can pin down structural correlations. We introduce the method of correlograph variance as a promising means of independently measuring the volume fraction of a paracrystalline composite. From comparisons with published data, we affirm that only a composite material of paracrystalline and continuous random network that is substantially paracrystalline could explain the existing experimental data, and point the way to more precise measurements on amorphous semiconductors. The results are of general interest for other classes of disordered materials.

  5. Intrinsic electron trapping in amorphous oxide

    Science.gov (United States)

    Strand, Jack; Kaviani, Moloud; Afanas’ev, Valeri V.; Lisoni, Judit G.; Shluger, Alexander L.

    2018-03-01

    We demonstrate that electron trapping at intrinsic precursor sites is endemic in non-glass-forming amorphous oxide films. The energy distributions of trapped electron states in ultra-pure prototype amorphous (a)-HfO2 insulator obtained from exhaustive photo-depopulation experiments demonstrate electron states in the energy range of 2–3 eV below the oxide conduction band. These energy distributions are compared to the results of density functional calculations of a-HfO2 models of realistic density. The experimental results can be explained by the presence of intrinsic charge trapping sites formed by under-coordinated Hf cations and elongated Hf–O bonds in a-HfO2. These charge trapping states can capture up to two electrons, forming polarons and bi-polarons. The corresponding trapping sites are different from the dangling-bond type defects responsible for trapping in glass-forming oxides, such as SiO2, in that the traps are formed without bonds being broken. Furthermore, introduction of hydrogen causes formation of somewhat energetically deeper electron traps when a proton is immobilized next to the trapped electron bi-polaron. The proposed novel mechanism of intrinsic charge trapping in a-HfO2 represents a new paradigm for charge trapping in a broad class of non-glass-forming amorphous insulators.

  6. Characterization of Amorphous and Co-Amorphous Simvastatin Formulations Prepared by Spray Drying

    Directory of Open Access Journals (Sweden)

    Goedele Craye

    2015-12-01

    Full Text Available In this study, spray drying from aqueous solutions, using the surface-active agent sodium lauryl sulfate (SLS as a solubilizer, was explored as a production method for co-amorphous simvastatin–lysine (SVS-LYS at 1:1 molar mixtures, which previously have been observed to form a co-amorphous mixture upon ball milling. In addition, a spray-dried formulation of SVS without LYS was prepared. Energy-dispersive X-ray spectroscopy (EDS revealed that SLS coated the SVS and SVS-LYS particles upon spray drying. X-ray powder diffraction (XRPD and differential scanning calorimetry (DSC showed that in the spray-dried formulations the remaining crystallinity originated from SLS only. The best dissolution properties and a “spring and parachute” effect were found for SVS spray-dried from a 5% SLS solution without LYS. Despite the presence of at least partially crystalline SLS in the mixtures, all the studied formulations were able to significantly extend the stability of amorphous SVS compared to previous co-amorphous formulations of SVS. The best stability (at least 12 months in dry conditions was observed when SLS was spray-dried with SVS (and LYS. In conclusion, spray drying of SVS and LYS from aqueous surfactant solutions was able to produce formulations with improved physical stability for amorphous SVS.

  7. Systematic review of the prevalence of bipolar disorder and bipolar spectrum disorders in population-based studies.

    Science.gov (United States)

    Dell'Aglio, José Caetano; Basso, Lissia Ana; Argimon, Irani Iracema de Lima; Arteche, Adriane

    2013-01-01

    This paper describes the findings of a systematic literature review aimed at providing an overview of the lifetime prevalence of bipolar disorder and bipolar spectrum disorders in population-based studies. Databases MEDLINE, ProQuest, Psychnet, and Web of Science were browsed for papers published in English between 1999 and May 2012 using the following search string: bipolar disorders OR bipolar spectrum disorders AND prevalence OR cross-sectional OR epidemiology AND population-based OR non-clinical OR community based. The search yielded a total of 434 papers, but only those published in peer-reviewed journals and with samples aged ≥ 18 years were included, resulting in a final sample of 18 papers. Results revealed rather heterogeneous findings concerning the prevalence of bipolar disorders and bipolar spectrum disorders. Lifetime prevalence of bipolar disorder ranged from 0.1 to 7.5%, whereas lifetime prevalence of bipolar spectrum disorders ranged from 2.4 to 15.1%. Differences in the rates of bipolar disorder and bipolar spectrum disorders may be related to the consideration of subthreshold criteria upon diagnosis. Differences in the prevalence of different subtypes of the disorder are discussed in light of diagnostic criteria and instruments applied.

  8. Systematic review of the prevalence of bipolar disorder and bipolar spectrum disorders in population-based studies

    Directory of Open Access Journals (Sweden)

    José Caetano Dell'Aglio Jr.

    2013-01-01

    Full Text Available This paper describes the findings of a systematic literature review aimed at providing an overview of the lifetime prevalence of bipolar disorder and bipolar spectrum disorders in population-based studies. Databases MEDLINE, ProQuest, Psychnet, and Web of Science were browsed for papers published in English between 1999 and May 2012 using the following search string: bipolar disorders OR bipolar spectrum disorders AND prevalence OR cross-sectional OR epidemiology AND population-based OR non-clinical OR community based. The search yielded a total of 434 papers, but only those published in peer-reviewed journals and with samples aged ≥ 18 years were included, resulting in a final sample of 18 papers. Results revealed rather heterogeneous findings concerning the prevalence of bipolar disorders and bipolar spectrum disorders. Lifetime prevalence of bipolar disorder ranged from 0.1 to 7.5%, whereas lifetime prevalence of bipolar spectrum disorders ranged from 2.4 to 15.1%. Differences in the rates of bipolar disorder and bipolar spectrum disorders may be related to the consideration of subthreshold criteria upon diagnosis. Differences in the prevalence of different subtypes of the disorder are discussed in light of diagnostic criteria and instruments applied.

  9. Abordagens psicoterápicas no transtorno bipolar Psychoterapeutic approach in bipolar disorder

    Directory of Open Access Journals (Sweden)

    Paulo Knapp

    2005-01-01

    Full Text Available Embora o tratamento farmacológico seja essencial para o tratamento do transtorno bipolar, apenas 40% de todos os pacientes que aderem às medicações permanecem assintomáticos durante o período de seguimento, o que tem levado ao desenvolvimento de intervenções psicoterápicas associadas. O objetivo deste artigo é examinar as evidências atuais da eficácia de intervenções psicoterápicas no tratamento do transtorno bipolar. Foi realizada uma pesquisa bibliográfica por meio do MedLine, PsychoINFO, Lilacs e Cochrane Data Bank, até o ano de 2004, em que foram procurados artigos originais e revisões sobre as abordagens psicoterápicas utilizadas no tratamento do transtorno bipolar. Há várias abordagens que podem se mostrar úteis no tratamento do transtorno bipolar. A psicoeducação e a terapia cognitivo-comportamental apresentam as evidências mais consistentes e são as técnicas mais amplamente estudadas. As intervenções envolvendo familiares e a terapia interpessoal e de ritmo social se mostram tratamentos eficazes em determinadas situações. Há alguns estudos empregando a terapia psicodinâmica no transtorno bipolar, mas são estudos com limitações metodológicas. Apesar de haver evidências demonstrando a eficácia de determinadas abordagens psicoterápicas no transtorno bipolar, ainda é necessária a realização de estudos posteriores que comprovem tais dados e que desenvolvam tratamentos baseados em modelos etiológicos e que identifiquem tratamentos específicos para as diferentes fases e tipos de transtorno bipolar.Although pharmacological treatment is essential for treating bipolar disorder, less than half of all medication compliant patients are non-symptomatic during follow-up, which has led to developments of adjunctive psychosocial interventions. This paper examines the current evidence for effectiveness of psychotherapeutic interventions in the treatment of bipolar disorder. Searches were undertaken through Med

  10. Ge /Si heteronanocrystal floating gate memory

    Science.gov (United States)

    Li, Bei; Liu, Jianlin; Liu, G. F.; Yarmoff, J. A.

    2007-09-01

    Metal oxide semiconductor field effect transistor memories with Ge /Si heteronanocrystals (HNCs) as floating gate were fabricated and characterized. Ge /Si HNCs with density of 5×1011cm-2 were grown on n-type Si (100) substrate with thin tunnel oxide on the top. Enhanced device performances including longer retention time, faster programming speed, and higher charge storage capability are demonstrated compared with Si nanocrystal (NC) memories. The erasing speed and endurance performance of Ge /Si HNC memories are similar to that of Si NC devices. The results suggest that Ge /Si HNCs may be an alternative to make further floating gate memory scaling down possible.

  11. Clinical status of comorbid bipolar disorder and borderline personality disorder.

    Science.gov (United States)

    Parker, Gordon; Bayes, Adam; McClure, Georgia; Del Moral, Yolanda Romàn Ruiz; Stevenson, Janine

    2016-09-01

    The status and differentiation of comorbid borderline personality disorder and bipolar disorder is worthy of clarification. To determine whether comorbid borderline personality disorder and bipolar disorder are interdependent or independent conditions. We interviewed patients diagnosed with either a borderline personality disorder and/or a bipolar condition. Analyses of participants grouped by DSM diagnoses established that those with comorbid conditions scored similarly to those with a borderline personality disorder alone on all key variables (i.e. gender, severity of borderline personality scores, developmental stressors, illness correlates, self-injurious behaviour rates) and differed from those with a bipolar disorder alone on nearly all non-bipolar item variables. Similar findings were returned for groups defined by clinical diagnoses. Comorbid bipolar disorder and borderline personality disorder is consistent with the formal definition of comorbidity in that, while coterminous, individuals meeting such criteria have features of two independent conditions. © The Royal College of Psychiatrists 2016.

  12. Does bipolar pacemaker current activate blood platelets?

    DEFF Research Database (Denmark)

    Gjesdal, Grunde; Hansen, Annebirthe Bo; Brandes, Axel

    2009-01-01

    to the pacemaker can. METHODS: Platelet-rich plasma was prepared from two healthy subjects. Platelet reactivity to the agonist ADP was tested in paired samples in an aggregometer in a case/control setup. RESULTS: Eighteen of 46 tested pairs of platelet-rich plasma showed increased reactivity in the paced sample......OBJECTIVE: The aim of this study was to investigate whether bipolar pacemaker current lead can activate blood platelets. The null hypothesis was that 1 minute of electrical stimulation of platelets would not influence their subsequent reactivity to adenosine diphosphate (ADP). BACKGROUND: Both...... platelets and muscle cells contain actin and myosin filaments, and both cells are activated following calcium influx. Muscle cells open their calcium channels and contract when exposed to an electric current. Current through a bipolar pacemaker lead will expose a small volume of blood, including platelets...

  13. Bias in emerging biomarkers for bipolar disorder

    DEFF Research Database (Denmark)

    Carvalho, A F; Köhler, C A; Fernandes, B S

    2016-01-01

    BACKGROUND: To date no comprehensive evaluation has appraised the likelihood of bias or the strength of the evidence of peripheral biomarkers for bipolar disorder (BD). Here we performed an umbrella review of meta-analyses of peripheral non-genetic biomarkers for BD. METHOD: The Pubmed/Medline, E......BACKGROUND: To date no comprehensive evaluation has appraised the likelihood of bias or the strength of the evidence of peripheral biomarkers for bipolar disorder (BD). Here we performed an umbrella review of meta-analyses of peripheral non-genetic biomarkers for BD. METHOD: The Pubmed....../Medline, EMBASE and PsycInfo electronic databases were searched up to May 2015. Two independent authors conducted searches, examined references for eligibility, and extracted data. Meta-analyses in any language examining peripheral non-genetic biomarkers in participants with BD (across different mood states...

  14. Udvikling af medicinsk behandling mod bipolar lidelse

    DEFF Research Database (Denmark)

    Ellegaard, Pernille Kempel

    2015-01-01

    Selvom Esbjerg ligger i vandkants Danmark, er det den Psykiatriske Forskningsenhed i denne by, der er primus motor for et stort forsøg blandt mennesker, der lider af bipolar lidelse. Forsøget hedder ”NACOS”, og er et medicinsk forsøg til mennesker, der befinder sig i den depressive fase.......Selvom Esbjerg ligger i vandkants Danmark, er det den Psykiatriske Forskningsenhed i denne by, der er primus motor for et stort forsøg blandt mennesker, der lider af bipolar lidelse. Forsøget hedder ”NACOS”, og er et medicinsk forsøg til mennesker, der befinder sig i den depressive fase....

  15. Bipolar zinc/oxygen battery development

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, S. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Schlatter, C. [Swiss Federal Inst. of Technology, Lausanne (Switzerland)

    1997-06-01

    A bipolar electrically rechargeable Zn/O{sub 2} battery has been developed. Reticulated copper foam served as substrate for the zinc deposit on the anodic side, and La{sub 0.6}Ca{sub 0.4}CoO{sub 3}-catalyzed bifunctional oxygen electrodes were used on the cathodic side of the cells. The 100 cm{sup 2} unit cell had an open circuit voltage of 1,4 V(O{sub 2}) in moderately alkaline electrolyte. The open circuit voltage and the peak power measured for a stack containing seven cells were ca. 10V and 90W, respectively. The current-potential behaviour was determined as a function of the number of bipolar cells, and the maximum discharge capacity was determined at different discharge rates. (author) 4 figs., 1 ref.

  16. High rate lithium/thionyl chloride bipolar battery development

    Science.gov (United States)

    Russell, P. G.; Goebel, F.

    The lithium/thionyl chloride ( {Li}/{SOCl2}) electrochemistry is capable of providing high power and high specific power, especially under pulse discharge conditions, when cells containing thin components are arranged in a bipolar configuration. This paper describes recent work concerned with bipolar cell design, cathode evaluation, component manufacturing methods, and the assembly and testing of bipolar modules containing up to 150 cells for Sonobuoy application.

  17. High rate lithium-thionyl chloride bipolar battery development

    Energy Technology Data Exchange (ETDEWEB)

    Russell, P.G.; Goebel, F. [Yardney Technical Products, Inc., Pawcatuck, CT (United States)

    1994-12-31

    The lithium/thionyl chloride system is capable of providing both high power and high energy density when cells containing thin components are arranged in a bipolar configuration. Electrode current densities in excess of 300mA/cm{sup 2} are achieved during pulse discharge. The present work is concerned with bipolar cell design, cathode evaluation, component manufacturing methods, and the assembly and testing of bipolar modules containing up to 150 cells.

  18. High rate lithium/thionyl chloride bipolar battery development

    Energy Technology Data Exchange (ETDEWEB)

    Russell, P.G. [Yardney Technical Products, Inc., Pawcatuck, CT (United States); Goebel, F. [Yardney Technical Products, Inc., Pawcatuck, CT (United States)

    1995-04-01

    The lithium/thionyl chloride (Li/SOCl{sub 2}) electrochemistry is capable of providing high power and high specific power, especially under pulse discharge conditions, when cells containing thin components are arranged in a bipolar configuration. This paper describes recent work concerned with bipolar cell design, cathode evaluation, component manufacturing methods, and the assembly and testing of bipolar modules containing up to 150 cells for Sonobuoy application. (orig.)

  19. The bipolar II disorder personality traits, a true syndrome?

    Science.gov (United States)

    Gudmundsson, Einar

    2015-06-01

    The author was struck by the similarities and commonality of complaints, aside from mood swings, made by Bipolar II patients and started registrating these complaints. This registrational work eventually led to the development of The Bipolar II Syndome Checklist. The aim of this work was to understand how widely the Bipolar II disorder affects the personality, and what disturbing personality traits are the most common? Deliberately, no attempt was made to diagnose psychiatric comorbidities, in the hope that one would get a clearer view of what symptoms, if any, could be considered a natural part of the Bipolar II Disorder. As far as the author knows this is a novel approach. 105 Bipolar II patients completed the Bipolar II Syndrome Checklist. The answers to the 44 questions on the list are presented in tables. Symptoms like anxiety, low self esteem, paranoia, extreme hurtfulness, migraine, Post Partum Depression, obsessive traits, alcoholism in the family are amongst the findings which will be presented in greater detail. No control group. Bipolar I patients excluded. The Bipolar II Syndrome Checklist has not been systematically validated. The results show that Bipolar II Disorder causes multiple symptoms so commonly that it may be justified to describe it as a syndrome, The Bipolar II Syndrome. Also these disturbances commonly lie in families of Bipolar II patients and are in all likelihood, greatly underdiagnosed. The clinical relevance of this study lies in increasing our knowledge and understanding of the nature of the Bipolar II Disorder, which in all probability will increase the diagnostic and treatment accuracy, since clinicians are more likely to scan for other symptoms needing treatment. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. The relationship between borderline personality disorder and bipolar disorder

    OpenAIRE

    Zimmerman, Mark; Morgan, Theresa A.

    2013-01-01

    It is clinically important to recognize both bipolar disorder and borderline personality disorder (BPD) in patients seeking treatment for depression, and it is important to distinguish between the two. Research considering whether BPD should be considered part of a bipolar spectrum reaches differing conclusions. We reviewed the most studied question on the relationship between BPD and bipolar disorder: their diagnostic concordance. Across studies, approximately 10% of patients with BPD had bi...