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Sample records for hughes alex hall

  1. Auxiliary Library Explorer (ALEX) Development

    Science.gov (United States)

    2016-02-01

    schema development • Structured Query Language (SQL) database development • data mining • interface development • data visualisation and analysis. These...product of ALEX was a web front-end. In Section 5, we describe how this front-end was generated. Some descriptive analysis of the structure of DST Group’s...the data from Wikipedia Miner [9] to inform semantic analytics and relevance of technical terms. Unfortunately this requires a Hadoop cluster with at

  2. Necrology: Hugh Carson Cutler

    Directory of Open Access Journals (Sweden)

    David L. Browman

    1999-05-01

    Full Text Available Hugh Carson Cutler, forner curator of Economic Botany at the Missouri Botanical Gardens, was one of the first generation paleoethnobotanists in this country. A pioneer in the field, and instrumental in getting American archaeologists to begin to employ flotation techniques for recovery of botanical remains. Cutler, the son of Manuel and Mary Cutler. was born September 8. 1912 in Milwaukee. Wisconsin. and died September 22, 1998 in Topeka, Kansas.

  3. Alex Sanchez's Fiction: A Resource for All

    Science.gov (United States)

    Meyers, G. Douglas

    2009-01-01

    The young adult novels of Alex Sanchez belong in every high school English classroom and media center. With compelling plots and significant themes, Sanchez's six novels create numerous rich learning opportunities for students. In this article, the author describes how Sanchez's novels on lesbian, gay, bisexual, and transgender themes can be…

  4. The Many Worlds of Hugh Everett III

    CERN Document Server

    ,

    2011-01-01

    A review of Peter Byrne's biography of Hugh Everett III, "The Many Worlds of Hugh Everett III: Multiple Universes, Mutual Assured Destruction, and the Meltdown of a Nuclear Family", (Oxford University Press, 2010).

  5. A guide to Hughes' syndrome.

    Science.gov (United States)

    Sheehan, Tina Louise

    Hughes' syndrome, or antiphospholipid syndrome, is thought to be the cause of one in four strokes in people aged less than 40 years. It is an antiinflammatory autoimmune disorder in which the blood has a tendency to clot too quickly. It can affect any artery or vein in the body and the main symptoms are thrombosis, pregnancy loss and the presence of antibodies. If detected it can be treated effectively.

  6. The Blues Poetry of Langston Hughes

    Science.gov (United States)

    Waldron, Edward E.

    1971-01-01

    The author discusses the criteria of the blues as an American art form. He then shows how Langston Hughes captures the mood, the feeling, the rhythm and the impact of the blues in his poetry. (Author/LF)

  7. Entrevista com o Dr. Alex Shankland

    Directory of Open Access Journals (Sweden)

    Luciana BENEVIDES

    2013-12-01

    Full Text Available Pesquisador do Institute of Development Studies (IDS da Universidade de Sussex, Inglaterra, Alex Shankland é cientista social e já trabalhou como pesquisador, gestor de organizações não governamentais e consultor em desenvolvimento social em diversos países, entre os quais o Brasil, o Peru, o México, a Índia, Angola, Moçambique e o próprio Reino Unido. Suas áreas de pesquisa incluem as práticas de cooperação internacional (com enfoque na relação Brasil-África, a governança democrática, a participação social nos sistemas de saúde e o desenho de políticas públicas para minorias étnicas e outras populações marginalizadas. O tema de seu doutorado foi representação indígena e política de saúde na Amazônia brasileira. Tem mais de 20 anos de experiência como coordenador de programas e projetos, entre os quais a consultoria realizada para o Projeto Vigisus II/Funasa para definição dos modelos de atenção, de organização, de gestão, de financiamento e de monitoramento e de avaliação do Subsistema de Atenção à Saúde Indígena.

  8. Langston Hughes and his poem "Harlem"

    Institute of Scientific and Technical Information of China (English)

    郝红

    2005-01-01

    @@ James Langston Hughes was born February 1,1902, in Joplin, Missouri. His parents divorced when he was a small child, and his father moved to Mexico. He was raised by his Grandmother until he was thirteen, when he moved to Lincoln,Illinois, to live with his mother and her husband, eventually settling in Cleveland, Ohio.

  9. Hugh Maaskant : architect van de vooruitgang

    NARCIS (Netherlands)

    Provoost, M.

    2003-01-01

    Hugh Maaskant (1907–1977) is best known as the architect who made the biggest mark on the post-war reconstruction of Rotterdam with such buildings as the Groothandelsgebouw, the Hilton Hotel and the Lijnbaan flats. Beginning his career in 1937 as the partner of Willem van Tijen, Maaskant embarked on

  10. Responses to Hugh Heclo's "On Thinking Institutionally"

    Science.gov (United States)

    Fennell, Robert C.; Ascough, Richard S.; Liew, Tat-siong Benny; McLain, Michael; Westfield, Nancy Lynne

    2010-01-01

    Hugh Heclo's recent book "On Thinking Institutionally" (Paradigm Publishers, 2008) analyzes changes that have taken place in the past half century in how North Americans tend to think and act in institutions. The volume is receiving particular attention as it can be applied to higher education and to religious denominations, and so deserves…

  11. Hugh Maaskant : architect van de vooruitgang

    NARCIS (Netherlands)

    Provoost, Michelle

    2003-01-01

    Hugh Maaskant (1907–1977) is best known as the architect who made the biggest mark on the post-war reconstruction of Rotterdam with such buildings as the Groothandelsgebouw, the Hilton Hotel and the Lijnbaan flats. Beginning his career in 1937 as the partner of Willem van Tijen, Maaskant embarked on

  12. Obituary: Lawrence Hugh Aller, 1913-2003

    Science.gov (United States)

    Kaler, James B.

    2003-12-01

    Michigan, he taught a two-semester course in advanced general astronomy that covered nearly everything, in addition to a remarkable four-semester sequence in astrophysics (general, stellar atmospheres, nebular astrophysics, and stellar interiors). These were backed up by an extraordinary set of books. In 1943, Goldberg and he turned out the seminal toms, Stars, and Nebulae. (A solo third edition was published in 1991.) Then in 1953 arrived "The Atmospheres of the Sun and Stars" (revised a decade later), a tour de force on the physics of stellar plasmas and radiative transfer that became the bible of a generation of astronomers. "Nuclear Transformations, Stellar Interiors, and Nebulae" appeared a year later, and "Gaseous Nebulae" two years after that (rewritten in 1984 as "Physics of Thermal Gaseous Nebulae"). Not having a computer available in the early years, he used his students, creating mammoth "Aller Problems" that solved the equations for results that went into the books. Never formally published were two massive tomes of advanced general astronomy. To those of us lucky enough to have them, they serve as references to this day. His students, both undergraduate and graduate, are everywhere, their own students in turn carrying on Lawrence's ideas and work. In 1941, Lawrence married Rosalind Duncan Hall (who survives), and together they raised three children: Hugh, Gwen, and Raymond. Not only did one son become an astronomer, but so has one granddaughter (a dynasty established). Lawrence was absorbed by news and politics. He hated injustice of any kind, and let you know about it. He could entertain for hours with stories of his youth and of other astronomers, never realizing that he would also be the source of affectionate stories that would be told and retold by his own students. Of beautiful heart, he was a good father, both to his own children and to those he adopted as his students, none of whom, having been taught by him, will ever forget. Incredibly prolific, his

  13. On the Hughes model and numerical aspects

    KAUST Repository

    Gomes, Diogo A.

    2017-01-05

    We study a crowd model proposed by R. Hughes in [11] and we describe a numerical approach to solve it. This model comprises a Fokker-Planck equation coupled with an eikonal equation with Dirichlet or Neumann data. First, we establish a priori estimates for the solutions. Second, we study radial solutions and identify a shock formation mechanism. Third, we illustrate the existence of congestion, the breakdown of the model, and the trend to the equilibrium. Finally, we propose a new numerical method and consider two examples.

  14. Hugh Maaskant: architect van de vooruitgang

    OpenAIRE

    Provoost, M.

    2003-01-01

    Hugh Maaskant (1907–1977) is best known as the architect who made the biggest mark on the post-war reconstruction of Rotterdam with such buildings as the Groothandelsgebouw, the Hilton Hotel and the Lijnbaan flats. Beginning his career in 1937 as the partner of Willem van Tijen, Maaskant embarked on his most prolific period after establishing an independent practice in 1955. He produced the lion’s share of his work in the 1950s and ’60s, the very period architectural critics generally regard ...

  15. Donald Hugh Blocher (1928-2013).

    Science.gov (United States)

    Dowd, E Thomas

    2015-01-01

    This article memorializes Donald Hugh Blocher (1928-2013). Blocher, a giant in counseling psychology, was elected a fellow of the American Psychological Association (APA) in 1973, received a Distinguished Achievement Award from Harvard University in 1968, and served as president of APA Division 17 (Society of Counseling Psychology) in 1980. He obtained a Fulbright Lectureship at the University of Keele (United Kingdom) for 1968-1969, where he helped develop a counseling psychology program according to American standards. He also published many books, book chapters, and articles over the course of his professional career.

  16. Hugh Owen Thomas (1834-1891)

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    @@ Hugh Owen Thomas被称为英国骨科之父,他对英国乃至世界骨科作出了杰出的贡献. 早在17世纪,接骨师已经作为一个社会地位较高的职业在英国、法国兴盛起来.接骨师的技术通常是在家族内部传承而不会对外传授.

  17. Sandy ja Hugh - paar või mitte? / Hugh Grant, Sandra Bullock

    Index Scriptorium Estoniae

    Grant, Hugh, 1960-

    2003-01-01

    Romantilises komöödias "Kaks nädalat armumiseks" ("Two Weeks Notice"), režissöör Marc Lawrence, mängivad kaks kuulsat näitlejat. Staarid oma suhetest : Hugh Grant : "Sandra on geenius"; Sandra Bullock : "Oleme temaga nagu kaksikud!"

  18. Sandy ja Hugh - paar või mitte? / Hugh Grant, Sandra Bullock

    Index Scriptorium Estoniae

    Grant, Hugh, 1960-

    2003-01-01

    Romantilises komöödias "Kaks nädalat armumiseks" ("Two Weeks Notice"), režissöör Marc Lawrence, mängivad kaks kuulsat näitlejat. Staarid oma suhetest : Hugh Grant : "Sandra on geenius"; Sandra Bullock : "Oleme temaga nagu kaksikud!"

  19. Hall C

    Data.gov (United States)

    Federal Laboratory Consortium — Hall C's initial complement of equipment (shown in the figure), includes two general-purpose magnetic spectrometers. The High Momentum Spectrometer (HMS) has a large...

  20. Hall A

    Data.gov (United States)

    Federal Laboratory Consortium — The instrumentation in Hall A at the Thomas Jefferson National Accelerator Facility was designed to study electroand photo-induced reactions at very high luminosity...

  1. Acute Charles Bonnet Syndrome following Hughes procedure.

    Science.gov (United States)

    Wilson, Michelle E; Pointdujour-Lim, Renelle; Lally, Sara; Shields, Carol L; Rabinowitz, Michael P

    2016-10-01

    A 69-year-old male experienced monocular formed visual hallucinations after occlusion of the right eye following resection of eyelid basal cell carcinoma and reconstruction with a Hughes procedure (tarsoconjunctival flap). His symptoms included recurrent, well-defined, organized, complex, formed images of small children playing in the snow. These visual phenomena occurred only in the occluded eye, began several hours after surgery, and recurred intermittently several times daily for 4 days, lasting several minutes with each occurrence. The patient retained insight into the false nature of the images throughout the duration of his symptoms, and the hallucinations resolved spontaneously while the flap was still in place. To our knowledge, this is the first reported case of Charles Bonnet Syndrome (CBS) following a Hughes procedure in a patient with normal visual acuity in the non-occluded fellow eye. Unlike other reported cases of acute onset CBS following transient monocular occlusion, hallucinations in the occluded eye remitted prior to restoration of vision in the occluded eye. Ophthalmologists should be aware of the potential for CBS following even transient monocular occlusion and should consider warning patients about its potential to occur.

  2. Visual text hallucinations of thoughts in an alexic woman.

    Science.gov (United States)

    Yamagata, Bun; Kobayashi, Hitomi; Yamamoto, Hideki; Mimura, Masaru

    2014-04-15

    In this report we describe a patient with a clinical diagnosis of dementia with Lewy bodies, who had hallucinations of reading her thoughts in the air although she was alexic and unable to read. She also had severe visuoperceptual deficits and closing-in phenomenon. SPECT imaging demonstrated hypoperfusion of the left parieto-occipital cortices together with hyperperfusion of the left orbitofronto-temporal areas. Her visual text hallucinations may represent another type of textual hallucinations related to syntacto-semantic network hyperactivation, which is implicated in auditory hallucinations in schizophrenia.

  3. On Social and Organisational Psychology: Interview with Alex Haslam

    Directory of Open Access Journals (Sweden)

    Vlad Glăveanu

    2012-08-01

    Full Text Available In this interview Prof. Alex Haslam discusses his past and present work in social and organisational psychology and the multiple ways in which these two fields are inter-connected. He considers the guiding threads within his scientific activity from the famous BBC Prison Study to more recent work on leadership. Covering both theoretical to applied considerations, this interview addresses important questions for psychologists working in organisations and elsewhere in society. It offers a glimpse into the fascinating world of humans as social beings capable of forming groups and sharing identities, of including but also excluding, of both following and leading.

  4. A Dance Class, a Drag King, & the Pedagogical Possibilities of Performative Hip-Hop: An Interview with Carmen Morrison & Alex U. Inn

    Science.gov (United States)

    Schönfeldt-Aultman, Scott M.; Morrison, Carmen

    2015-01-01

    Alex U. Inn is the co-founder and one of the two MCs of the hip-hop drag king group, Momma's Boyz. Momma's Boyz celebrated their tenth anniversary in 2014. Carmen Morrison is the offstage name of Alex U. Inn, though "Carmen" now goes by Alex offstage, as well. Within this interview, the names "Carmen" and "Alex" are…

  5. Hugh Blairs Lectures on Rhetoric and Belles Lettres

    DEFF Research Database (Denmark)

    Schatz-Jakobsen, Claus

    1989-01-01

    Artiklen nærlæser dekonstruktivt dele af den skotske retorikprofessor Hugh Blairs Lecures on Rhetoric and Belles Lettres (1783) og påviser splittelsen mellem to vidt forskellige retorik- og liltteraturhistoriske interesser, neoklassicistiske vs. romantiske....

  6. Síndrome de Hughes-Stovin

    Directory of Open Access Journals (Sweden)

    Sonia Pankl

    2015-04-01

    Full Text Available El síndrome de Hughes-Stovin es una entidad infrecuente caracterizada por trombosis venosa profunda y aneurismas de la arteria pulmonar, siendo su etiología y patogenia desconocida. Algunos autores la consideran una variante de la enfermedad de Behcet. Su curso natural es generalmente fatal. Se presenta con tos, disnea, hemoptisis, dolor torácico y fiebre. El tratamiento es con esteroides y agentes citotóxicos hasta la cirugía. Presentamos el caso de un hombre de 41 años que consultó por disnea, hemoptisis y dolor torácico, llegándose al diagnóstico de trombosis venosa profunda de miembro inferior derecho, trombo-embolismo de pulmón y aneurismas de arterias pulmonares. Recibió tratamiento con corticoides en altas dosis y 6 pulsos de ciclofosfamida de 1 gramo durante 6 meses, con regresión completa de los aneurismas y de la sintomatología.

  7. Healthy Dining Hall Eating

    Science.gov (United States)

    ... A Week of Healthy Breakfasts Shyness Healthy Dining Hall Eating KidsHealth > For Teens > Healthy Dining Hall Eating ... likely to eat. previous continue Overcoming Common Dining Hall Mistakes Even the most attentive diners can still ...

  8. A Behavioral Look at the Training of Alex: A Review of Pepperberg's "The Alex Studies: Cognitive and Communicative Abilities of Grey Parrots"

    Science.gov (United States)

    Hesse, Bruce E.; Potter, Bill

    2004-01-01

    "The Alex Studies: Cognitive and Communicative Abilities of Grey Parrots" by Irene Pepperberg is reviewed from a behavior analytic orientation. The results of the majority of her experiments are discussed in terms drawn from the general literature of behavior analysis and Skinner's analysis of verbal behavior. We conclude that she has provided…

  9. Radiologic diagnosis of Fitz-Hugh-Curtis syndrome

    Institute of Scientific and Technical Information of China (English)

    WANG Cheng-lin; GUO Xue-jun; YUAN Zhi-dong; SHI Qiao; HU Xiao-hong; FANG Lin

    2009-01-01

    @@ Litz-Hugh-Curtis syndrome (FHCS) was reported by Curtis after he found a fibrous adhesion between the surface of the liver and peritoneum in patients with gonococcal pelvic inflammation during laparoscopy in 1930, and the first report by Fitz-Hugh as acute gonococcal peritonitis in the right upper quadrant abdomen was published in 1934.1,2 The so-called FHCS is believed to originate from an inflammation in the pelvis which may ascend toward the diaphragmatic surface of the liver along the right paracolic gutters to cause the inflammation of the liver caosule with right upper abdominal pain.3-7

  10. Francesca Hughes: Architecture of Error: Matter, Measure and the Misadventure of Precision

    DEFF Research Database (Denmark)

    Foote, Jonathan

    2016-01-01

    Review of "Architecture of Error: Matter, Measure and the Misadventure of Precision" by Francesca Hughes (MIT Press, 2014)......Review of "Architecture of Error: Matter, Measure and the Misadventure of Precision" by Francesca Hughes (MIT Press, 2014)...

  11. Hugh Grant's Image Restoration Discourse: An Actor Apologizes.

    Science.gov (United States)

    Benoit, William L.

    1997-01-01

    Examines the strategies used by actor Hugh Grant (in his appearances on talk shows) to help restore his reputation after he was arrested for lewd behavior with a prostitute. Uses this case as a springboard to contrast entertainment image repair with political and corporate image repair, arguing that important situational differences can be…

  12. Additional Responses to Hugh Heclo's "On Thinking Institutionally"

    Science.gov (United States)

    Lincoln, Timothy D.; Fennell, Robert C.

    2011-01-01

    Issue 13:3 of this journal (July 2010) included a "Conversation" on Hugh Heclo's recent publication "On Thinking Institutionally" (Paradigm Publishers, 2008) with a book review by Robert Fennell and responses by Richard Ascough, Tat-siong Benny Liew, Michael McLain, and Lynne Westfield. Here we publish two additional responses to this same book.…

  13. Vernon Hughes and the Quest for the Proton's Spin

    Science.gov (United States)

    Jaffe, Robert L.

    2004-12-01

    Vernon Hughes dedicated much of the latter part of his career to the question "What carries the spin of the proton?" The question remains unanswered and near the top of the list of fascinating questions in QCD. I present a perspective on the question and Vernon's pursuit of an answer.

  14. Dr. Vernon W. Hughes, 81, authority on the subatomic

    CERN Multimedia

    Lavietes, S

    2002-01-01

    "Dr. Vernon W. Hughes, a Yale physicist whose investigation of particles called muons poked holes in standard subatomic theory and provided evidence for the existence of previously undetected matter, died at Yale-New Haven Hospital last Tuesday" (1/2 page).

  15. Hugh Hefner - maailma esi-playboy / Neeme Raud

    Index Scriptorium Estoniae

    Raud, Neeme, 1969-

    2004-01-01

    Ajakirja Playboy asutajast Hugh Hefner'ist, tema elufilosoofiast ja põhimõtetest erootikaväljaande sisu kujundamisel. Ärijuhi Christie Hefner'i sõnul on rahvusvahelise multimeedia-meelelahutusfirma praeguseks eesmärgiks brändi sobitamine erinevatesse meediavormidesse. Lisa: Mis on Playboy?

  16. Differential Response: What to Make of the Existing Research? A Response to Hughes et al.

    Science.gov (United States)

    Drake, Brett

    2013-01-01

    This article is a response to "Issues in Differential Response", a review of the current evidence pertaining to differential response (DR) programs in child protective services (CPS). In my view, the Hughes, Rycus, Saunders-Adams, Hughes, and Hughes article suffers from several weaknesses. First, DR programs are critiqued as if they were…

  17. Langston Hughes and his poem “Harlem”

    Institute of Scientific and Technical Information of China (English)

    郝红

    2005-01-01

    James Langston Hughes was born February 1. 1902, in Joplin, Missouri. His parents divorced when he was a small child, and his father moved to Mexico. He was raised by his Grandmother until he was thirteen, when he moved to Lincoln,Illinois, to live with his mother and her husband, eventually settling in Cleveland, Ohio. It was in I,incoln, Illinois, that Hughes began writing poetry. Following graduation, he spent a year in Mexico and a year at Columbia University. During these years, he held old jobs as an assistant cook, launderer, and a busboy, and traveled to Africa and Europe working as a seaman. In November 1924, he moved to Washington,

  18. Fitz-Hugh-Curtis综合征7例

    Institute of Scientific and Technical Information of China (English)

    焦浦生

    2000-01-01

    @@ FHC综合征Fitz-Hugh-Curtis Syntrome)是继发于盆腔感染的肝包膜炎症反应性疾病.该综合征典型临床表现是右上腹痛,发热伴有盆腔炎.现将我院近年来诊治FHC综合征7例总结中下.

  19. Bifurcaciones del Sistema de FitzHugh-Nagumo (FHN

    Directory of Open Access Journals (Sweden)

    Fernando Ongay Larios

    2011-01-01

    Full Text Available La familia paramétrica de los sistemas de FitzHugh-Nagumo es rica en bifurcaciones (Rocsoreanu et al., 2000. En este artículo estudiamos las bifurcaciones silla-nodo y de Hopf desde el punto de vista matemático de esta familia y se describen completamente los conjuntos de bifurcación en el espacio de parámetros.

  20. The Spin Structure of the Nucleon:. a Hughes Legacy

    Science.gov (United States)

    Cates, Gordon D.

    2004-12-01

    More than any other individual, Vernon Hughes can be pointed to as the father of the experimental investigation of nucleon spin structure. Even theoretical development in this area was spurred on by Vernon's pioneering efforts to make the control of spin degrees of freedom an experimental reality. This talk traces some of Vernon's work in this area, as well as examining, briefly and not in a complete fashion, some of the other work that can be looked upon as Vernon's legacy.

  1. Remembrance of Hugh E. Huxley, a founder of our field.

    Science.gov (United States)

    Pollard, Thomas D; Goldman, Yale E

    2013-09-01

    Hugh E. Huxley (1924-2013) carried out structural studies by X-ray fiber diffraction and electron microscopy that established how muscle contracts. Huxley's sliding filament mechanism with an ATPase motor protein taking steps along an actin filament, established the paradigm not only for muscle contraction but also for other motile systems using actin and unconventional myosins, microtubules and dynein and microtubules and kinesin.

  2. Sir Alex Fergusons otte ledelsesprincipper – tilfører de ledelsesdisciplinen nye indsigter?

    DEFF Research Database (Denmark)

    Agger Nielsen, Jeppe

    2015-01-01

    Fodbold og (offentlig) ledelse har umiddelbart ikke mange fællestræk, men der er måske inspiration at hente fra en af de mest anerkendte fodboldmanagers gennem tiden. I hvert fald er Sir Alex Fergusons ledelsesformular blevet en del af pensum på Harvard Business School. Men giver det virkelig god...

  3. Hugh de Wardener - the Man and the Scientist.

    Science.gov (United States)

    Phillips, M E; de Wardener, S

    2016-02-01

    Hugh de Wardener died on 29th September 2013, ten days before his 98th birthday. He had a diverse upbringing and qualified in Medicine in 1939. He joined the army but was captured in 1942 and imprisoned in Singapore and Thailand until 1945. His clinical care of fellow prisoners was highly regarded. He preserved their clinical records and used them, post-war, to write two Lancet papers. One showed, for the first time, that Wernickes encephalopathy could be caused by severe malnutrition and cured by small doses of vitamin B1. His later academic interests were based on the emphasis he placed on renal physiology. This applied to the topic most associated with his name-Natriuretic Hormone. Whilst de Wardener never isolated this hormone, his early experiments, demonstrating that a third factor other than GFR and aldosterone affected renal sodium transport, were substantiated by others. Hugh had many research interests: pyelonephritis, renal histology, maintenance dialysis and metabolic/renal bone disease. In his later years he researched intensively into the role of sodium and salt in the aetiology of essential hypertension. Hugh was president of the International Society of Nephrology (1969-72) and the UK Renal Association (1975-78). He received many awards and recognitions from across the world, many of them after his (so-called) retirement. Throughout his career he never neglected the care of his patients. As Bob Schrier wrote in his obituary of de Wardener in Kidney International he was a caring physicianwhose dedication to his patients welfare was exemplary.

  4. Some Numerical Aspects on Crowd Motion - The Hughes Model

    KAUST Repository

    Gomes, Diogo A.

    2016-01-06

    Here, we study a crowd model proposed by R. Hughes in [5] and we describe a numerical approach to solve it. This model comprises a Fokker-Planck equation coupled with an Eikonal equation with Dirichlet or Neumann data. First, we establish a priori estimates for the solution. Second, we study radial solutions and identify a shock formation mechanism. Third, we illustrate the existence of congestion, the breakdown of the model, and the trend to the equilibrium. Finally, we propose a new numerical method and consider two numerical examples.

  5. Quantum Spin Hall Effect

    Energy Technology Data Exchange (ETDEWEB)

    Bernevig, B.Andrei; Zhang, Shou-Cheng; /Stanford U., Phys. Dept.

    2010-01-15

    The quantum Hall liquid is a novel state of matter with profound emergent properties such as fractional charge and statistics. Existence of the quantum Hall effect requires breaking of the time reversal symmetry caused by an external magnetic field. In this work, we predict a quantized spin Hall effect in the absence of any magnetic field, where the intrinsic spin Hall conductance is quantized in units of 2 e/4{pi}. The degenerate quantum Landau levels are created by the spin-orbit coupling in conventional semiconductors in the presence of a strain gradient. This new state of matter has many profound correlated properties described by a topological field theory.

  6. Surviving To Write and Writing To Survive: The Complex Case of Langston Hughes.

    Science.gov (United States)

    Ostrom, Hans

    Studying the life of Langston Hughes in the context of how to teach freshman composition can shed light on two sometimes conflicting pedagogies, the expressivist and the social-constructionist. A discouraging period of fierce criticism, illness, depression, and financial woes coincided with Hughes' 39th birthday, which his biographer Arnold…

  7. Skyrmions and Hall Transport

    Science.gov (United States)

    Kim, Bom Soo; Shapere, Alfred D.

    2016-09-01

    We derive a generalized set of Ward identities that captures the effects of topological charge on Hall transport. The Ward identities follow from the (2 +1 )-dimensional momentum algebra, which includes a central extension proportional to the topological charge density. In the presence of topological objects like Skyrmions, we observe that the central term leads to a direct relation between the thermal Hall conductivity and the topological charge density. We extend this relation to incorporate the effects of a magnetic field and an electric current. The topological charge density produces a distinct signature in the electric Hall conductivity, which is identified in existing experimental data and yields further novel predictions. For insulating materials with translation invariance, the Hall viscosity can be directly determined from the Skyrmion density and the thermal Hall conductivity to be measured as a function of momentum.

  8. The Progression About Fitz-Hugh-Curtis Syndrome Study%Fitz-Hugh-Curtis综合征研究进展

    Institute of Scientific and Technical Information of China (English)

    靳翠平; 尚玉敏

    2009-01-01

    Fitz-Hugh-Curtis综合征是盆腔感染合并肝周围炎,主要涉及肝包膜而无肝实质损害,在慢性盆腔炎患者中较为常见.病原菌主要是淋病奈瑟菌及衣原体,主要临床表现为右下腹痛,并可导致慢性腹痛、不孕、异位妊娠等多种并发症.可结合腹腔CT、相关实验室检验及腹腔镜检查对其进行诊断及鉴别诊断,并通过敏感抗生素及腹腔镜手术进行有效治疗.就Fitz-Hugh-Curtis综合征病因与发病机制、临床特征、并发症、诊断、治疗及相关意义进行综述.

  9. A Powerful Friendship: Theodore von Karman and Hugh L. Dryden

    Science.gov (United States)

    Gorn, Michael

    2003-01-01

    During their long personal friendship and professional association, Theodore von Karman (1882-1963) and Hugh L. Dryden (1898-1965) exercised a pivotal if somewhat elusive influence over American aeronautics and spaceflight. Both decisive figures in organizing scientists and engineers at home and abroad, both men of undisputed eminence in their technical fields, their range of contacts in government, academia, the armed forces, industry, and professional societies spanned the globe to an extent unparalleled then as now. Moreover, because they coordinated their activities closely, their combined influence far exceeded the sum of each one s individual contributions. This paper illustrates their personal origins as well as the foundations of their friendship, how their relationship became a professional alliance, and their joint impact on the world of aeronautics and astronautics during the twentieth century.

  10. Realistic model of compact VLSI FitzHugh-Nagumo oscillators

    Science.gov (United States)

    Cosp, Jordi; Binczak, Stéphane; Madrenas, Jordi; Fernández, Daniel

    2014-02-01

    In this article, we present a compact analogue VLSI implementation of the FitzHugh-Nagumo neuron model, intended to model large-scale, biologically plausible, oscillator networks. As the model requires a series resistor and a parallel capacitor with the inductor, which is the most complex part of the design, it is possible to greatly simplify the active inductor implementation compared to other implementations of this device as typically found in filters by allowing appreciable, but well modelled, nonidealities. We model and obtain the parameters of the inductor nonideal model as an inductance in series with a parasitic resistor and a second order low-pass filter with a large cut-off frequency. Post-layout simulations for a CMOS 0.35 μm double-poly technology using the MOSFET Spice BSIM3v3 model confirm the proper behaviour of the design.

  11. Right Pleural Effusion in Fitz-Hugh-Curtis Syndrome

    Directory of Open Access Journals (Sweden)

    Tajiri,Takuma

    2006-10-01

    Full Text Available Right pleural effusion was diagnosed in a 36-year-old woman with right upper quadrant pain and fever. Enhanced pelvic computed tomography performed because of irregular genital bleeding revealed the pelvic inflammatory disease. Upon further questioning, the patient confirmed that she had recently undergone therapy for Chlamydia trachomatis infection. Therefore she was given an injection of tetracycline because we suspected Fitz-Hugh-Curtis syndrome (FHCS, a pelvic inflammatory disease characterized by perihepatitis associated with chlamydial infection. A remarkable clinical response to antibiotics was noted. The right upper quadrant pain was due to perihepatitis, and the final diagnosis was FHCS. Right pleural effusion may be caused by inflammation of the diaphragm associated with perihepatitis. Once chlamydial infection reaches the subphrenic liver, conditions in the closed space between the liver and diaphragm due to inflammatory adhesion may be conductive to chlamydial proliferation. The possibility of FHCS should be considered in patients and carefully distinguished from other abdominal diseases.

  12. Halls Lake 1990

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Salt marsh habitats along the shoreline of Halls Lake are threatened by wave erosion, but the reconstruction of barrier islands to reduce this erosion will modify or...

  13. General footage ISOLDE experimental hall

    CERN Multimedia

    2016-01-01

    Overview of the ISOLDE experimental hall. Equipment and experiments. Taken from the WITCH / EBIS platform: ISOLDE hall infrastructure, GHM line, LA1, LA2, LA0, central beamline, COLLAPS experiment, CRIS experiment, ISOLTRAP experiment, laser guidance from building 508 into the hall for laser spectroscopy COLLAPS and CRIS. Taken from the HIE ISOLDE shielding tunnel roof: ISOLDE hall infrastructure, WITCH experiment, VITO line, TAS experiment. General footage: High Tension room entrance and EBIS platform, staircases and passages in the experimental hall.

  14. Alex Houen. Powers of Possibility: Experimental American Writing since the 1960s.

    Directory of Open Access Journals (Sweden)

    Despoina Feleki

    2012-04-01

    Full Text Available After building a socio-political background on Fredric Jameson’s late capitalist postmodernism, Michel Foucault’s “biopolitics,” Herbert Marcuse’s “automatization” of social life and György Lukács’s “abstract” and “concrete” potentials, Alex Houen investigates in his work Powers of Possibility: Experimental American Writing since the 1960s (2012 the main political and technological events which have had a decisive impact on cultural production since the 60s in the U.S. Since Vietnam War, Col...

  15. Site-Specific Insertion Polymorphism of the MITE Alex-1 in the Genus Coffea Suggests Interspecific Gene Flow

    Directory of Open Access Journals (Sweden)

    Christine Dubreuil-Tranchant

    2011-01-01

    Full Text Available Miniature Inverted-repeat Transposable Elements (MITEs are small nonautonomous class-II transposable elements distributed throughout eukaryotic genomes. We identified a novel family of MITEs (named Alex in the Coffea canephora genome often associated with expressed sequences. The Alex-1 element is inserted in an intron of a gene at the CcEIN4 locus. Its mobility was demonstrated by sequencing the insertion site in C. canephora accessions and Coffea species. Analysis of the insertion polymorphism of Alex-1 at this locus in Coffea species and in C. canephora showed that there was no relationship between the geographical distribution of the species, their phylogenetic relationships, and insertion polymorphism. The intraspecific distribution of C. canephora revealed an original situation within the E diversity group. These results suggest possibly greater gene flow between species than previously thought. This MITE family will enable the study of the C. canephora genome evolution, phylogenetic relationships, and possible gene flows within the Coffea genus.

  16. Hughes, Twain, Child, and Sanger: Four Who Locked Horns with the Censors

    Science.gov (United States)

    Meltzer, Milton

    1969-01-01

    A look at the lives and conflicts of four writers--Langston Hughes, Mark Twain, Lydia Maria Child, and Margaret Sanger--who faced public criticism and censorship because oftheir views on controversial issues. (RM)

  17. Nonlocal Anomalous Hall Effect

    Science.gov (United States)

    Zhang, Steven S.-L.; Vignale, Giovanni

    2016-04-01

    The anomalous Hall (AH) effect is deemed to be a unique transport property of ferromagnetic metals, caused by the concerted action of spin polarization and spin-orbit coupling. Nevertheless, recent experiments have shown that the effect also occurs in a nonmagnetic metal (Pt) in contact with a magnetic insulator [yttrium iron garnet (YIG)], even when precautions are taken to ensure that there is no induced magnetization in the metal. We propose a theory of this effect based on the combined action of spin-dependent scattering from the magnetic interface and the spin-Hall effect in the bulk of the metal. At variance with previous theories, we predict the effect to be of first order in the spin-orbit coupling, just as the conventional anomalous Hall effect—the only difference being the spatial separation of the spin-orbit interaction and the magnetization. For this reason we name this effect the nonlocal anomalous Hall effect and predict that its sign will be determined by the sign of the spin-Hall angle in the metal. The AH conductivity that we calculate from our theory is in order of magnitude agreement with the measured values in Pt /YIG structures.

  18. Conducting Wall Hall Thrusters

    Science.gov (United States)

    Goebel, Dan M.; Hofer, Richard R.; Mikellides, Ioannis G.; Katz, Ira; Polk, James E.; Dotson, Brandon

    2013-01-01

    A unique configuration of the magnetic field near the wall of Hall thrusters, called Magnetic Shielding, has recently demonstrated the ability to significantly reduce the erosion of the boron nitride (BN) walls and extend the life of Hall thrusters by orders of magnitude. The ability of magnetic shielding to minimize interactions between the plasma and the discharge chamber walls has for the first time enabled the replacement of insulating walls with conducting materials without loss in thruster performance. The boron nitride rings in the 6 kW H6 Hall thruster were replaced with graphite that self-biased to near the anode potential. The thruster efficiency remained over 60% (within two percent of the baseline BN configuration) with a small decrease in thrust and increase in Isp typical of magnetically shielded Hall thrusters. The graphite wall temperatures decreased significantly compared to both shielded and unshielded BN configurations, leading to the potential for higher power operation. Eliminating ceramic walls makes it simpler and less expensive to fabricate a thruster to survive launch loads, and the graphite discharge chamber radiates more efficiently which increases the power capability of the thruster compared to conventional Hall thruster designs.

  19. Nonlocal Anomalous Hall Effect.

    Science.gov (United States)

    Zhang, Steven S-L; Vignale, Giovanni

    2016-04-01

    The anomalous Hall (AH) effect is deemed to be a unique transport property of ferromagnetic metals, caused by the concerted action of spin polarization and spin-orbit coupling. Nevertheless, recent experiments have shown that the effect also occurs in a nonmagnetic metal (Pt) in contact with a magnetic insulator [yttrium iron garnet (YIG)], even when precautions are taken to ensure that there is no induced magnetization in the metal. We propose a theory of this effect based on the combined action of spin-dependent scattering from the magnetic interface and the spin-Hall effect in the bulk of the metal. At variance with previous theories, we predict the effect to be of first order in the spin-orbit coupling, just as the conventional anomalous Hall effect-the only difference being the spatial separation of the spin-orbit interaction and the magnetization. For this reason we name this effect the nonlocal anomalous Hall effect and predict that its sign will be determined by the sign of the spin-Hall angle in the metal. The AH conductivity that we calculate from our theory is in order of magnitude agreement with the measured values in Pt/YIG structures.

  20. Investidura com a doctor honoris causa de l'Excm. Sr. Hugh Scott Fogler

    OpenAIRE

    Diversos autors

    2016-01-01

    Investidura com a doctor honoris causa del senyor Hugh Scott Fogler. Sessió acadèmica extraordinària, 15 d'abril de 2016. Elogi del candidat a càrrec del doctor Azael Fabregat Llagostera. Discurs d’investidura pronunciat pel senyor Hugh Scott Fogler. Paraules de benvinguda pronunciades pel doctor Josep Anton Ferré Vidal, Rector Magfc. de la Universitat.

  1. STS-40 Payload Specialist Millie Hughes-Fulford trains in JSC's SLS mockup

    Science.gov (United States)

    1987-01-01

    STS-40 Payload Specialist Millie Hughes-Fulford conducts Spacelab Life Sciences 1 (SLS-1) Experiment No. 198, Pulmonary Function During Weightlessness, in JSC's Life Sciences Project Division (LSPD) SLS mockup located in the Bioengineering and Test Support Facility Bldg 36. Hughes-Fulford monitors instruments and settings on Rack 8's panels. Behind her in the center aisle are the body mass measurement device (foreground) and the stowed bicycle ergometer.

  2. Hall Effect in Quasicrystals

    Institute of Scientific and Technical Information of China (English)

    ZHOU Xiang; HU Cheng-zheng; GONG Ping; WANG Ai-jun

    2005-01-01

    The relations between Hall effect and symmetry are discussed for all 2- and 3 dimensional quasicrystals with crystallographically forbidden symmetries. The results show that the numbers of independent components of the Hall coefficient (RH) are one for 3-dimensional quasicrystals, two for those 2 dimensional quasicrystals whose symmetry group is non-Abelian, and three for those 2-dimensional quasicrystals whose symmetry group is Abelian, respectively. The quasicrystals with the same number of independent components have the same form of the components of RH.

  3. Hall effect in hopping regime

    Energy Technology Data Exchange (ETDEWEB)

    Avdonin, A., E-mail: avdonin@ifpan.edu.pl [Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warszawa (Poland); Skupiński, P. [Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warszawa (Poland); Grasza, K. [Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warszawa (Poland); Institute of Electronic Materials Technology, ul. Wólczyńska 133, 01-919 Warszawa (Poland)

    2016-02-15

    A simple description of the Hall effect in the hopping regime of conductivity in semiconductors is presented. Expressions for the Hall coefficient and Hall mobility are derived by considering averaged equilibrium electron transport in a single triangle of localization sites in a magnetic field. Dependence of the Hall coefficient is analyzed in a wide range of temperature and magnetic field values. Our theoretical result is applied to our experimental data on temperature dependence of Hall effect and Hall mobility in ZnO. - Highlights: • Expressions for Hall coefficient and mobility for hopping conductivity are derived. • Theoretical result is compared with experimental curves measured on ZnO. • Simultaneous action of free and hopping conduction channels is considered. • Non-linearity of hopping Hall coefficient is predicted.

  4. Hall Effect in a Plasma.

    Science.gov (United States)

    Kunkel, W. B.

    1981-01-01

    Describes an apparatus and procedure for conducting an undergraduate laboratory experiment to quantitatively study the Hall effect in a plasma. Includes background information on the Hall effect and rationale for conducting the experiment. (JN)

  5. Profiles in Courage:Auto Racing's Alex Zanardi%钢铁战士扎纳尔迪

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ September 15,2001.Lausitz,Germany.Demonstrating the nerve and racing skills thatmade him a two-time CART world champion,AlexZinardi has put together a brilliant performance taking the lead in the late stages of the race.

  6. Pulmonary cytotoxicity of secondary metabolites of Stachybotrys chartarum (Ehrenb.) Hughes.

    Science.gov (United States)

    Pieckova, Elena; Hurbankova, Marta; Cerna, Silvia; Pivovarova, Zuzana; Kovacikova, Zuzana

    2006-01-01

    Damp dwellings represent suitable conditions for extended indoor moulds. A cellulolytic micromycete Stachybotrys chartarum (Ehrenb.) Hughes is considered to be a tertiary colonizer of surfaces in affected buildings. Known adverse health effects of S. chartarum result from its toxins--trichothecenes or atranones, as well as spirolactams. Mechanism of their potential pathological effects on the respiratory tract has not yet been sufficiently clarified. The cytotoxic effects of complex chloroform-extractable endo- (in biomass) and exometabolites (in cultivation medium) of an indoor S. chartarum isolate of an atranone chemotype, grown on a liquid medium with yeast extract and sucrose at 25 degrees C for 14 d, on lung tissue were evaluated in the 3-day experiment. For the purpose, 4 mg of toxicants were intratracheally instilled in 200 g Wistar male rats. A trichothecene mycotoxin diacetoxyscirpenol was used as the positive control. Bronchoalveolar lavage (BAL) parameters--viability and phagocytic activity of alveolar macrophages (AM), activity of lactate dehydrogenase, acid phosphatase and cathepsin D in cell-free BAL fluid (BALF), as well as in BAL cells, were measured. Acute exposure to the metabolites caused statistically significant changes, indicating lung tissue injury in the experimental animals. Decreased AM viability and increased activity of lysosomal enzyme cathepsin D in BAL cells after fungal exometabolite exposure were the most impressive. As toxic principles were found predominantly in the growth medium, toxins were more likely responsible for lung cell damage than e.g. fungal cell wall components. S. chartarum toxic metabolites can contribute to the ill health of occupants of mouldy building after inhalation of contaminated aerosol.

  7. Laurance David Hall.

    Science.gov (United States)

    Coxon, Bruce

    2011-01-01

    An account is given of the life, scientific contributions, and passing of Laurance David Hall (1938-2009), including his early history and education at the University of Bristol, UK, and the synthesis and NMR spectroscopy of carbohydrates and other natural products during ∼20 years of research and teaching at the University of British Columbia in Vancouver, Canada. Lists of graduate students, post-doctoral fellows, and sabbatical visitors are provided for this period. Following a generous endowment by Dr. Herchel Smith, Professor Hall built a new Department of Medicinal Chemistry at Cambridge University, UK, and greatly expanded his researches into the technology and applications of magnetic resonance imaging (MRI) and zero quantum NMR. MRI technology was applied both to medical problems such as the characterization of cartilage degeneration in knee joints, the measurement of ventricular function, lipid localization in animal models of atherosclerosis, paramagnetic metal complexes of polysaccharides as contrast agents, and studies of many other anatomical features, but also to several aspects of materials analysis, including food analyses, process control, and the elucidation of such physical phenomena as the flow of liquids through porous media, defects in concrete, and the visualization of fungal damage to wood. Professor Hall's many publications, patents, lectures, and honors and awards are described, and also his successful effort to keep the Asilomar facility in Pacific Grove, California as the alternating venue for the annual Experimental NMR Conference. Two memorial services for Professor Hall are remembered.

  8. Strained graphene Hall bar

    Science.gov (United States)

    Milovanović, S. P.; Peeters, F. M.

    2017-02-01

    The effects of strain, induced by a Gaussian bump, on the magnetic field dependent transport properties of a graphene Hall bar are investigated. The numerical simulations are performed using both classical and quantum mechanical transport theory and we found that both approaches exhibit similar characteristic features. The effects of the Gaussian bump are manifested by a decrease of the bend resistance, R B, around zero-magnetic field and the occurrence of side-peaks in R B. These features are explained as a consequence of bump-assisted scattering of electrons towards different terminals of the Hall bar. Using these features we are able to give an estimate of the size of the bump. Additional oscillations in R B are found in the quantum description that are due to the population/depopulation of Landau levels. The bump has a minor influence on the Hall resistance even for very high values of the pseudo-magnetic field. When the bump is placed outside the center of the Hall bar valley polarized electrons can be collected in the leads.

  9. The Inhomogeneous Hall's Ray

    OpenAIRE

    Crisp, D J; W Moran; Pollington, A. D.

    2012-01-01

    We show that the inhomogenous approximation spectrum, associated to an irrational number \\alpha\\ always has a Hall's Ray; that is, there is an \\epsilon>0 such that [0,\\epsilon) is a subset of the spectrum. In the case when \\alpha\\ has unbounded partial quotients we show that the spectrum is just a ray.

  10. Hall Sweet Home

    Science.gov (United States)

    Oguntoyinbo, Lekan

    2011-01-01

    Many urban and commuter universities have their sights set on students who are unlikely to connect with the college and likely to fail unless the right strategies are put in place to help them graduate. In efforts to improve retention rates, commuter colleges are looking to an unusual suspect: residence halls. The author discusses how these…

  11. Photon thermal Hall effect

    CERN Document Server

    Ben-Abdallah, Philippe

    2015-01-01

    A near-field thermal Hall effect (i.e.Righi-Leduc effect) in lattices of magneto-optical particles placed in a constant magnetic field is predicted. This effect is related to a symetry breaking in the system induced by the magnetic field which gives rise to preferential channels for the heat-transport by photon tunneling thanks to the particles anisotropy tuning.

  12. The Monty Hall Dilemma

    NARCIS (Netherlands)

    Barteld Kooi, [No Value

    2006-01-01

    Samenvatting: In het begin van de jaren negentig brak een wereldwijde discussie los over een probleem dat in het Engels 'The Monty Hall Dilemma' wordt genoemd. Marilyn vos Savant, die in het Guinness Book of World Records wordt genoemd als degene met het

  13. Plasma Relaxation in Hall Magnetohydrodynamics

    CERN Document Server

    Shivamoggi, B K

    2011-01-01

    Parker's formulation of isotopological plasma relaxation process in magnetohydrodynamics (MHD) is extended to Hall MHD. The torsion coefficient alpha in the Hall MHD Beltrami condition turns out now to be proportional to the "potential vorticity." The Hall MHD Beltrami condition becomes equivalent to the "potential vorticity" conservation equation in two-dimensional hydrodynamics if the Hall MHD Lagrange multiplier beta is taken to be proportional to the "potential vorticity" as well. The winding pattern of the magnetic field lines in Hall MHD then appears to evolve in the same way as "potential vorticity" lines in 2D hydrodynamics.

  14. A Clockwork Orange (1971: suffers Alex DeLarge antisocial personality disorder?

    Directory of Open Access Journals (Sweden)

    Laura María GARCÍA LORENZO

    2016-09-01

    Full Text Available Many movies have featured characters in which we can identify characteristics related to a personality disorder. However, only a few have obtained such an accurate portrait that allows us to make without any difficulty a concrete diagnosis based in the medical criteria used for real patients. A clockwork orange (1971 by Stanley Kubrick is one of those. This paper aims to identify in the behavior of his main character, Alex DeLarge, the characteristic features of an antisocial personality disorder. For this purpose, the standard criteria are applied and thus a conclusion is made out of them.In the first part we make a short introduction about Kubrick’s works and this movie, along with some basic notes on the analyzed disorder.

  15. Clinical outcome of Fitz-Hugh-Curtis syndrome mimicking acute biliary disease

    Institute of Scientific and Technical Information of China (English)

    Seong Yong Woo; Jin Il Kim; Dae Young Cheung; Se Hyun Cho; Soo-Heon Park; Joon-Yeol Han; Jae Kwang Kim

    2008-01-01

    AIM: To analyze the clinical characteristics of patients diagnosed with Fitz-Hugh-Curtis syndrome.METHODS: The clinical courses of patients that visited St. Mary's Hospital with abdominal pain from January 2005 to December 2006 and were diagnosed with Fitz-Hugh-Curtis syndrome were examined.RESULTS: Fitz-Hugh-Curtis syndrome was identified in 22 female patients of childbearing age; their mean age was 31.0 + 8.1 years. Fourteen of these cases presented with pain in the upper right abdomen alone or together with pain in the lower abdomen,and six patients presented with pain only in the lower abdomen. The first impression at the time of visit was acute cholecystitis or cholangitis in 10 patients and acute appendicitis or pelvic inflammatory disease in eight patients. Twenty-one patients were diagnosed by abdominal computer tomograghy (CT), and the results of abdominal sonography were normal for 10 of these patients. Ch/amydia trichomatis was isolated from 18 patients. Two patients underwent laparoscopic adhesiotomy and 20 patients were completely cured by antibiotic treatment.CONCLUSION: For women of childbearing age with acute pain in the upper right abdomen alone or together with pain in the lower abdomen, Fitz-HughCurtis syndrome should be considered during differential diagnosis. Moreover, in cases suspected to be Fitz-HughCurtis syndrome, abdominal c-r, rather than abdominal sonography, assists in the diagnosis.

  16. Refining of wood waste from saw mills - a feasibility study for Alex sawmill; Foeraedling av saagverkens biprodukter - en oevergripande energi- och exergistudie oever Alex saag

    Energy Technology Data Exchange (ETDEWEB)

    Kullendorff, A.; Ryden, A. [SEP Scandinavian Energy Project AB (Sweden); Renstroem, R. [Karlstad Univ. (Sweden)

    1998-03-01

    An overall energy balance has been made for the Alex sawmill, with separate balances for the boiler and the timber dryer. Parallel to this energy balance, an exergy study has been compiled for the same systems. A heat demand has been identified from these balances and three different systems has been studied. Two of these imply a refinement of the by-products produced in the mill. System I: Hot water boiler as the present system; System II: Hot water boiler integrated with a back pressure dryer; System IIb: Hot water boiler integrated with a back pressure dryer and a plant for pelletizing the biofuel; System III: Steam boiler followed by power production integrated with a back pressure dryer; and System IIIb: Steam boiler followed by power production integrated with a back pressure dryer and a plant for pelletizing the biofuel. The study shows that System II seems to be the most interesting system from an energy and economical point of view with an additional revenue of about 15 MSEK/year. The dryer for this system is a newly developed not yet commercial atmospheric back pressure dryer especially suited for saw mills and small district heating companies. Other types of dryers could also be considered. Other types have not been evaluated here. The exergy study shows that the back pressure dryer almost double the yield of exergy, compared to the present situation. In addition to this, one has to take the fictitious 'profit in exergy' from the following combustion into account. If a steam boiler is installed instead of the hot water boiler, and power generation is added, then the exergy conservation will be improved even more compared to the system with the back pressure dryer. From an exergy point of view a system with power generation and back pressure drying will give an exergy yield of more than four times of that of todays system.

  17. Cylindrical geometry hall thruster

    Science.gov (United States)

    Raitses, Yevgeny; Fisch, Nathaniel J.

    2002-01-01

    An apparatus and method for thrusting plasma, utilizing a Hall thruster with a cylindrical geometry, wherein ions are accelerated in substantially the axial direction. The apparatus is suitable for operation at low power. It employs small size thruster components, including a ceramic channel, with the center pole piece of the conventional annular design thruster eliminated or greatly reduced. Efficient operation is accomplished through magnetic fields with a substantial radial component. The propellant gas is ionized at an optimal location in the thruster. A further improvement is accomplished by segmented electrodes, which produce localized voltage drops within the thruster at optimally prescribed locations. The apparatus differs from a conventional Hall thruster, which has an annular geometry, not well suited to scaling to small size, because the small size for an annular design has a great deal of surface area relative to the volume.

  18. Relativistic Hall Effect

    CERN Document Server

    Bliokh, Konstantin Y

    2011-01-01

    We consider the relativistic deformation of quantum waves and mechanical bodies carrying intrinsic angular momentum (AM). When observed in a moving reference frame, the centroid of the object undergoes an AM-dependent transverse shift. This is the relativistic analogue of the spin Hall effect, which occurs in free space without any external fields. Remarkably, the shifts of the geometric and energy centroids differ by a factor of 2, and both centroids are crucial for the correct Lorentz transformations of the AM tensor. We examine manifestations of the relativistic Hall effect in quantum vortices, mechanical flywheel, and discuss various fundamental aspects of the phenomenon. The perfect agreement of quantum and relativistic approaches allows applications at strikingly different scales: from elementary spinning particles, through classical light, to rotating black-holes.

  19. Planar Hall Effect MRAM

    OpenAIRE

    Bason, Y.; Klein, L.; Yau, J. -B.; Hong, X.; Hoffman, J.; Ahn, C. H.

    2005-01-01

    We suggest a new type of magnetic random access memory (MRAM) that is based on the phenomenon of the planar Hall effect (PHE) in magnetic films, and we demonstrate this idea with manganite films. The PHE-MRAM is structurally simpler than currently developed MRAM that is based on magnetoresistance tunnel junctions (MTJ), with the tunnel junction structure being replaced by a single layer film.

  20. Case of Fitz-Hugh-Curtis syndrome in male without presentation of sexually transmitted disease.

    Science.gov (United States)

    Yi, Haram; Shim, Chan Sup; Kim, Gyu Won; Kim, Jung Seok; Choi, In Zoo

    2015-11-16

    Fitz-Hugh-Curtis syndrome is a type of perihepatitis that causes liver capsular infection without infecting the hepatic parenchyma or pelvis. Fitz-Hugh-Curtis syndrome is known to occur commonly in women of childbearing age who do not use oral contraceptives and have sexual partners older than 25 years of age. However, the syndrome has been reported to occur rarely in males. The clinical symptoms are right upper quadrant pain and tenderness, and pleuritic right sided chest pain. The clinical presentation is similar in male and female. We experienced a case of Fitz-Hugh-Curtis syndrome in a 60-year-old man with the chief complaint of right upper quadrant abdominal pain. Despite a previous history of gonorrhea, we have also described our experiences of improved symptoms and recovery with allopathic medicines and have thereby reported the present case with a literature review.

  1. Real time optical edge enhancement using a Hughes liquid crystal light valve

    Science.gov (United States)

    Chao, Tien-Hsin

    1989-01-01

    The discovery of an edge enhancement effect in using a Hughes CdS liquid crystal light valve (LCLV) is reported. An edge-enhanced version of the input writing image can be directly obtained by operating the LCLV at a lower bias frequency and bias voltage. Experimental conditions in which this edge enhancement effect can be optimized are described. Experimental results show that the SNR of the readout image using this technique is superior to that obtained using high-pass filtering. The repeatability of this effect is confirmed by obtaining an edge enhancement result using two different Hughes LCLVs. The applicability of this effect to improve discrimination capability in optical pattern recognition is addressed. The results show that the Hughes LCLV can be used in both continuous tone and edge-enhancing modes by simply adjusting its bias conditions.

  2. On the Hughes' model for pedestrian flow: The one-dimensional case

    KAUST Repository

    Di Francesco, Marco

    2011-02-01

    In this paper we investigate the mathematical theory of Hughes\\' model for the flow of pedestrians (cf. Hughes (2002) [17]), consisting of a non-linear conservation law for the density of pedestrians coupled with an eikonal equation for a potential modelling the common sense of the task. For such an approximated system we prove existence and uniqueness of entropy solutions (in one space dimension) in the sense of Kružkov (1970) [22], in which the boundary conditions are posed following the approach of Bardos et al. (1979) [7]. We use BV estimates on the density ρ and stability estimates on the potential Π in order to prove uniqueness. Furthermore, we analyze the evolution of characteristics for the original Hughes\\' model in one space dimension and study the behavior of simple solutions, in order to reproduce interesting phenomena related to the formation of shocks and rarefaction waves. The characteristic calculus is supported by numerical simulations. © 2010 Elsevier Inc.

  3. Real time optical edge enhancement using a Hughes liquid crystal light valve

    Science.gov (United States)

    Chao, Tien-Hsin

    1989-01-01

    The discovery of an edge enhancement effect in using a Hughes CdS liquid crystal light valve (LCLV) is reported. An edge-enhanced version of the input writing image can be directly obtained by operating the LCLV at a lower bias frequency and bias voltage. Experimental conditions in which this edge enhancement effect can be optimized are described. Experimental results show that the SNR of the readout image using this technique is superior to that obtained using high-pass filtering. The repeatability of this effect is confirmed by obtaining an edge enhancement result using two different Hughes LCLVs. The applicability of this effect to improve discrimination capability in optical pattern recognition is addressed. The results show that the Hughes LCLV can be used in both continuous tone and edge-enhancing modes by simply adjusting its bias conditions.

  4. "Hall viscosity" and intrinsic metric of incompressible fractional Hall fluids

    OpenAIRE

    Haldane, F. D. M.

    2009-01-01

    The (guiding-center) "Hall viscosity" is a fundamental tensor property of incompressible ``Hall fluids'' exhibiting the fractional quantum Hall effect; it determines the stress induced by a non-uniform electric field, and the intrinsic dipole moment on (unreconstructed) edges. It is characterized by a rational number and an intrinsic metric tensor that defines distances on an ``incompressibility lengthscale''. These properties do not require rotational invariance in the 2D plane. The sign of ...

  5. Symposium Festschrift Hughes (Vernon W) to Celebrate his 70th birthday

    CERN Document Server

    1992-01-01

    The contents of this book are derived from a celebration of the 70th birthday of Vernon W Hughes. Professor Hughes' career has touched on several areas in modern physics ranging from precision measurements of the fundamental properties of atoms to measurements of spin structure functions of the proton via deep inelastic muon scattering at the world's highest energy fixed target machines. This observance of his 70th birthday brings together experimental and theoretical physicists who are leaders of the many fields in which he has made contributions.

  6. 77 FR 1975 - Union Pacific Railroad Company-Discontinuance of Service Exemption-in Pittsburg, Hughes, and...

    Science.gov (United States)

    2012-01-12

    ..., Hughes, and Seminole Counties, Okla. (the line). The line traverses United States Postal Service Zip... discontinue service over a portion of a line of railroad known as the Shawnee Branch Line, between milepost... in Hughes County, which makes the line 0.19 miles longer than the terminal mileposts would...

  7. Rivers and Hughes's Construction of Black Culture in White America——Textual Analysis of "The Negro Speaks of RAvers"

    Institute of Scientific and Technical Information of China (English)

    曾慧

    2009-01-01

    Langston Hughes's central purpose in writing is "to explain and illuminate the Negro condition in America". By means of textual analysis, this thesis is to discover how the images of rivers in "The Negro Speaks of Rivers" construct the black culture, to find Hughes's identity in America.

  8. Wheel of concert hall acoustics

    OpenAIRE

    Kuusinen, A.; Lokki, T.

    2017-01-01

    More than a hundred years of research on concert hall acoustics has provided an extensive list of attributes to describe and evaluate the perceptual aspects of sound in concert halls. This brief overview discusses the current knowledge, and presents a "wheel of concert hall acoustics" in which the main aspects are gathered together with the descriptive attributes that are commonly encountered in the research literature. Peer reviewed

  9. Thermal Hall Effect of Magnons

    Science.gov (United States)

    Murakami, Shuichi; Okamoto, Akihiro

    2017-01-01

    We review recent developments in theories and experiments on the magnon Hall effect. We derive the thermal Hall conductivity of magnons in terms of the Berry curvature of magnonic bands. In addition to the Dzyaloshinskii-Moriya interaction, we show that the dipolar interaction can make the Berry curvature nonzero. We mainly discuss theoretical aspects of the magnon Hall effect and related theoretical works. Experimental progress in this field is also mentioned.

  10. Magnesium Hall Thruster

    Science.gov (United States)

    Szabo, James J.

    2015-01-01

    This Phase II project is developing a magnesium (Mg) Hall effect thruster system that would open the door for in situ resource utilization (ISRU)-based solar system exploration. Magnesium is light and easy to ionize. For a Mars- Earth transfer, the propellant mass savings with respect to a xenon Hall effect thruster (HET) system are enormous. Magnesium also can be combusted in a rocket with carbon dioxide (CO2) or water (H2O), enabling a multimode propulsion system with propellant sharing and ISRU. In the near term, CO2 and H2O would be collected in situ on Mars or the moon. In the far term, Mg itself would be collected from Martian and lunar regolith. In Phase I, an integrated, medium-power (1- to 3-kW) Mg HET system was developed and tested. Controlled, steady operation at constant voltage and power was demonstrated. Preliminary measurements indicate a specific impulse (Isp) greater than 4,000 s was achieved at a discharge potential of 400 V. The feasibility of delivering fluidized Mg powder to a medium- or high-power thruster also was demonstrated. Phase II of the project evaluated the performance of an integrated, highpower Mg Hall thruster system in a relevant space environment. Researchers improved the medium power thruster system and characterized it in detail. Researchers also designed and built a high-power (8- to 20-kW) Mg HET. A fluidized powder feed system supporting the high-power thruster was built and delivered to Busek Company, Inc.

  11. Hall Effect Spintronics

    Science.gov (United States)

    2008-09-23

    in Fig. 1. An alternating current source operating at frequency f1 is attached to contacts B and D with a respective lock-in amplifier monitoring...that floats the signal and a transconductance amplifier . The input voltage of each lock-in amplifier is composed of two signals: the Hall voltage at...alternating current sources operating at frequencies f1 and f2 respectively. VAC and VDB are lock-in amplifiers set for the reference frequencies f2 and f1

  12. The Microwave Hall Effect

    OpenAIRE

    2015-01-01

    This paper describes a simple microwave apparatus to measure the Hall effect in semiconductor wafers. The advantage of this technique is that it does not require contacts on the sample or the use of a resonant cavity. Our method consists of placing the semiconductor wafer into a slot cut in an X-band (8 - 12 GHz) waveguide series tee, injecting microwave power into the two opposite arms of the tee, and measuring the microwave output at the third arm. A magnetic field applied perpendicular to ...

  13. IN MEMORIAM: Hugh P Kelly, 3 September 1931 - 29 June 1992

    Science.gov (United States)

    Hansen, Jørgen E.

    1993-01-01

    It is said that Racah was one of the few physicists who was able not only to read Hermann Weyl's book "The Theory of Groups and Quantum Mechanics" but also to understand enough to use it himself. Something similar applies to Hugh Kelly, who introduced the methods of Many-Body Perturbation Theory (MBPT), which was being developed by nuclear physicists like Keith Brueckner whom Hugh worked with as a post-doc, into atomic physics. Since atomic physics with its "known" forces is a perfect area in which to apply the methods of MBPT, it is clear that this would have happened sooner or later. Hugh Kelly's achievement is that it happened very early. Hugh's death this summer after a long battle with cancer is a great loss to atomic physics and to his many friends in the community. Hugh P Kelly got his PhD from the University of California at Berkeley in 1963 under the supervision of Kenneth Watson and in 1965 he was hired as assistant Professor at the University of Virginia. His appointment was to a large extent due to the support of M E Rose, also a nuclear physicist with interest in atoms as is clear from his book "Elementary Theory of Angular Momentum". Hugh remained at the University of Virginia for the rest of his life, over the years serving as Department Chairman, Faculty Dean and, during the last years, as University Provost, but throughout Hugh pursued his real passion which was Physics. It is a clear sign of his dedication that he is sole author on a large number of papers particularly of course in the early years when he alone was Atomic Theory in Charlottesville. Hugh contributed to many areas of atomic physics although early on photoionization became his favourite subject and the one where he made his main contribution: first for closed shell atoms, but later extending his techniques to open shell systems for which the normal MBPT techniques did not apply. Hugh had a good nose for finding projects that were of topical interest and many of his papers are

  14. 75 FR 24973 - United States v. Baker Hughes Inc., et al.

    Science.gov (United States)

    2010-05-06

    .... IV. Trade and Commerce A. Background 1. Overview of Drilling and Completion Process 11. Offshore... impose on each other's pricing. Post merger, Baker Hughes will likely find it profitable to raise the... transaction may present a profitable opportunity to remove one or two vessels from the Gulf, an opportunity...

  15. The Political Economy of Rhetorical Style: Hugh Blair's Response to the Civic-Commercial Dilemma

    Science.gov (United States)

    Longaker, Mark Garrett

    2008-01-01

    Recent scholarship treats Hugh Blair's "Lectures" on Rhetoric and Belles Lettres (1783) as an effort to endorse either the liberal or the civic political traditions in eighteenth-century Scotland. This essay questions this orthodoxy by reading the "Lectures", and in particular Blair's attention to considerations of rhetorical…

  16. Markov chain Monte Carlo approach to parameter estimation in the FitzHugh-Nagumo model

    DEFF Research Database (Denmark)

    Jensen, Anders Christian; Ditlevsen, Susanne; Kessler, Mathieu

    2012-01-01

    Excitability is observed in a variety of natural systems, such as neuronal dynamics, cardiovascular tissues, or climate dynamics. The stochastic FitzHugh-Nagumo model is a prominent example representing an excitable system. To validate the practical use of a model, the first step is to estimate m...

  17. Principles and Practices Fostering Inclusive Excellence: Lessons from the Howard Hughes Medical Institute's Capstone Institutions

    Science.gov (United States)

    DiBartolo, Patricia Marten; Gregg-Jolly, Leslie; Gross, Deborah; Manduca, Cathryn A.; Iverson, Ellen; Cooke, David B., III; Davis, Gregory K.; Davidson, Cameron; Hertz, Paul E.; Hibbard, Lisa; Ireland, Shubha K.; Mader, Catherine; Pai, Aditi; Raps, Shirley; Siwicki, Kathleen; Swartz, Jim E.

    2016-01-01

    Best-practices pedagogy in science, technology, engineering, and mathematics (STEM) aims for inclusive excellence that fosters student persistence. This paper describes principles of inclusivity across 11 primarily undergraduate institutions designated as Capstone Awardees in Howard Hughes Medical Institute's (HHMI) 2012 competition. The Capstones…

  18. The Political Economy of Rhetorical Style: Hugh Blair's Response to the Civic-Commercial Dilemma

    Science.gov (United States)

    Longaker, Mark Garrett

    2008-01-01

    Recent scholarship treats Hugh Blair's "Lectures" on Rhetoric and Belles Lettres (1783) as an effort to endorse either the liberal or the civic political traditions in eighteenth-century Scotland. This essay questions this orthodoxy by reading the "Lectures", and in particular Blair's attention to considerations of rhetorical style, against their…

  19. "Comments on Greenhow, Robelia, and Hughes": Expanding the New Literacies Conversation

    Science.gov (United States)

    Leu, Donald J.; O'Byrne, W. Ian; Zawilinski, Lisa; McVerry, J. Greg; Everett-Cacopardo, Heidi

    2009-01-01

    Using a popularized notion such as Web 2.0 limits research efforts by employing a binary construct, one initially prompted by commercial concerns. Instead, the authors of this article, commenting on Greenhow, Robelia, and Hughes (2009), suggest that continuous, not dichotomous, change in the technologies of literacy and learning defines the…

  20. The ISOLDE hall

    CERN Multimedia

    Maximilien Brice

    2002-01-01

    Since 1992, after its move from the 600 MeV SC, ISOLDE is a customer of the Booster (then 1 GeV, now 1.4 GeV). The intense Booster beam (some 3E13 protons per pulse) is directed onto a target, from which a mixture of isotopes emanates. After ionization and electrostatic acceleration to 60 keV, they enter one of the 2 spectrometers (General Purpose Separator: GPS, and High Resolution Separator: HRS) from which the selected ions are directed to the experiments. The photos show: the REX-ISOLDE post accelerator; the mini-ball experiment; an overview of the ISOLDE hall. In the picture (_12) of the hall, the separators are behind the wall. From either of them, beams can be directed into any of the many beamlines towards the experiments, some of which are visible in the foreground. The elevated cubicle at the left is EBIS (Electron Beam Ion Source), which acts as a charge-state multiplier for the REX facility. The ions are further mass analzyzed and passed on to the linac which accelerates them to higher energies. T...

  1. Cosmopolitanism - Conversation with Stuart Hall

    OpenAIRE

    Hall, Stuart

    2006-01-01

    Forty minute conversation between Stuart Hall and Pnina Werbner, filmed and edited by Haim Bresheeth. Synopsis by Sarah Harrison. Conversation between Stuart Hall and Pnina Werbner on the theme of Cosmopolitanism (to be shown at the Association of Social Anthropologists Silver Jubilee conference in 2006), in March 2006

  2. Hall Effect Gyrators and Circulators

    Science.gov (United States)

    Viola, Giovanni; DiVincenzo, David P.

    2014-04-01

    The electronic circulator and its close relative the gyrator are invaluable tools for noise management and signal routing in the current generation of low-temperature microwave systems for the implementation of new quantum technologies. The current implementation of these devices using the Faraday effect is satisfactory but requires a bulky structure whose physical dimension is close to the microwave wavelength employed. The Hall effect is an alternative nonreciprocal effect that can also be used to produce desired device functionality. We review earlier efforts to use an Ohmically contacted four-terminal Hall bar, explaining why this approach leads to unacceptably high device loss. We find that capacitive coupling to such a Hall conductor has much greater promise for achieving good circulator and gyrator functionality. We formulate a classical Ohm-Hall analysis for calculating the properties of such a device, and show how this classical theory simplifies remarkably in the limiting case of the Hall angle approaching 90°. In this limit, we find that either a four-terminal or a three-terminal capacitive device can give excellent circulator behavior, with device dimensions far smaller than the ac wavelength. An experiment is proposed to achieve GHz-band gyration in millimeter (and smaller) scale structures employing either semiconductor heterostructure or graphene Hall conductors. An inductively coupled scheme for realizing a Hall gyrator is also analyzed.

  3. Hugh E. Huxley: cambiando el paradigma de la contracción muscular, desde dentro. [Hugh E. Huxley: changing from inside the paradigm of muscle contraction].

    OpenAIRE

    Adolfo Araci

    2014-01-01

    Desde un punto de vista físico se puede entender la fibra muscular como un motor, es decir, un sistema capaz de transformar la energía química en energía mecánica, que se utiliza para realizar un trabajo. Por lo tanto, para entender cómo ocurre dicho proceso de transformación es necesario conocer la ultraestructura de la fibra muscular. Esta es, sin duda, la principal aportación al acervo científico del recientemente fallecido Hugh Emor Huxley (1924-2013). Huxley se graduó en Física en el Chr...

  4. Hugh E. Huxley: cambiando el paradigma de la contracción muscular, desde dentro. [Hugh E. Huxley: changing from inside the paradigm of muscle contraction].

    OpenAIRE

    Adolfo Araci

    2014-01-01

    Desde un punto de vista físico se puede entender la fibra muscular como un motor, es decir, un sistema capaz de transformar la energía química en energía mecánica, que se utiliza para realizar un trabajo. Por lo tanto, para entender cómo ocurre dicho proceso de transformación es necesario conocer la ultraestructura de la fibra muscular. Esta es, sin duda, la principal aportación al acervo científico del recientemente fallecido Hugh Emor Huxley (1924-2013). Huxley se graduó en Física en el Chr...

  5. Topological Hall and spin Hall effects in disordered skyrmionic textures

    KAUST Repository

    Ndiaye, Papa Birame

    2017-02-24

    We carry out a thorough study of the topological Hall and topological spin Hall effects in disordered skyrmionic systems: the dimensionless (spin) Hall angles are evaluated across the energy-band structure in the multiprobe Landauer-Büttiker formalism and their link to the effective magnetic field emerging from the real-space topology of the spin texture is highlighted. We discuss these results for an optimal skyrmion size and for various sizes of the sample and find that the adiabatic approximation still holds for large skyrmions as well as for nanoskyrmions. Finally, we test the robustness of the topological signals against disorder strength and show that the topological Hall effect is highly sensitive to momentum scattering.

  6. Tuning giant anomalous Hall resistance ratio in perpendicular Hall balance

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, J. Y.; Yang, G. [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083 (China); State Key Laboratory of Magnetism, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Wang, S. G., E-mail: sgwang@iphy.ac.cn, E-mail: ghyu@mater.ustb.edu.cn [State Key Laboratory of Magnetism, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Liu, J. L. [State Key Laboratory of Magnetism, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Department of Physics, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China); Wang, R. M. [Department of Physics, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China); Amsellem, E.; Kohn, A. [Department of Materials Engineering, Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer-Sheva 84105 (Israel); Yu, G. H., E-mail: sgwang@iphy.ac.cn, E-mail: ghyu@mater.ustb.edu.cn [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083 (China)

    2015-04-13

    Anomalous Hall effect at room temperature in perpendicular Hall balance with a core structure of [Pt/Co]{sub 4}/NiO/[Co/Pt]{sub 4} has been tuned by functional CoO layers, where [Pt/Co]{sub 4} multilayers exhibit perpendicular magnetic anisotropy. A giant Hall resistance ratio up to 69 900% and saturation Hall resistance (R{sub S}{sup P}) up to 2590 mΩ were obtained in CoO/[Pt/Co]{sub 4}/NiO/[Co/Pt]{sub 4}/CoO system, which is 302% and 146% larger than that in the structure without CoO layers, respectively. Transmission electron microscopy shows highly textured [Co/Pt]{sub 4} multilayers and oxide layers with local epitaxial relations, indicating that the crystallographic structure has significant influence on spin dependent transport properties.

  7. City and Town Halls; townHalls13

    Data.gov (United States)

    University of Rhode Island Geospatial Extension Program — Locations of city and town halls in Rhode Island. Derived using information originally compiled by the State of Rhode Island (http://www.ri.gov), and built upon...

  8. Ward Identities for Hall Transport

    CERN Document Server

    Hoyos, Carlos; Oz, Yaron

    2014-01-01

    We derive quantum field theory Ward identities based on linear area preserving and conformal transformations in 2+1 dimensions. The identities relate Hall viscosities, Hall conductivities and the angular momentum. They apply both for relativistic and non relativistic systems, at zero and at finite temperature. We consider systems with or without translation invariance, and introduce an external magnetic field and viscous drag terms. A special case of the identities yields the well known relation between the Hall conductivity and half the angular momentum density.

  9. [Preserved implicit reading and the recovery of explicit reading in a pure alexic].

    Science.gov (United States)

    Hashimoto, R; Tanaka, Y

    1996-03-01

    We described a 55-year-old, right-handed, university-educated Japanese man who showed pure alexia after an infarction in the territory of the left posterior cerebral artery. Damage to the corpus callosum was limited to the most caudal part of the splenium. In the early days of his illness, he demonstrated the inability to read aloud on either Kana (Japanese syllabograms) or Kanji (Japanese morphograms). In contrast, he could semantically categorize Kanji-words such as animals or non-animals. Subsequently, he gradually regained the ability of reading aloud Kanji as well as Kana. At that time, we further investigated the relation between his reading ability and the attributes of 881 Kanji characters including hieroglyphicity, concreteness, and familiarity. We found that he could more readily read Kanjis with higher hieroglyphicity, concreteness, and familiarity. The reading times for Kanji-words were significantly shorter than those of corresponding Kana-words. Moreover, he showed some difficulty to read Kana-words and Kana combinations without meaning when asked to perform repetitive opposing movements with his thumb and little finger inhibiting kinesthetic reading. The effect was not observed when he read Kanji-words. These results lead us to suggest the following: (1) the two components of reading, reading aloud and comprehension abilities, are dissociable in a pure alexic, especially in Kanji reading; and (2) recovery mechanisms underlying Kanji and Kana reading were different in our case. Namely, restitution of the direct connection through the residual splenium fibers between the visual word form processing area in the right hemisphere and the left angular gyrus was attributed to Kanji reading, and utilization of kinesthetic reading played an important role in Kana reading.

  10. Planar Hall effect bridge magnetic field sensors

    DEFF Research Database (Denmark)

    Henriksen, A.D.; Dalslet, Bjarke Thomas; Skieller, D.H.

    2010-01-01

    Until now, the planar Hall effect has been studied in samples with cross-shaped Hall geometry. We demonstrate theoretically and experimentally that the planar Hall effect can be observed for an exchange-biased ferromagnetic material in a Wheatstone bridge topology and that the sensor signal can...... Hall effect bridge sensors....

  11. Fitz-Hugh-Curtis syndrome: abdominal pain in women of 26 years old Síndrome de Fitz-Hugh-Curtis: dolor abdominal en mujer de 26 años

    OpenAIRE

    Liseth Rivero-Sánchez; Elsa María López-Soriano; Luisa Guarner-Aguilar

    2011-01-01

    Fitz-Hugh-Curtis syndrome is an inflammation of the liver capsule as a complication of pelvic inflammatory disease, whose most common etiologic agent is the C. trachomatis. The acute phase of the Fitz-Hugh-Curtis syndrome may present itself with pain in right upper abdomen, commonly confused with other hepatobiliary and gastrointestinal tract diseases. Definitive diagnosis is now possible with non-invasive techniques such as ultrasound, computed tomography, as well as techniques to isolate th...

  12. Shared Magnetics Hall Thruster Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In the proposed Phase II program, Busek Co. will demonstrate an innovative methodology for clustering Hall thrusters into a high performance, very high power...

  13. Shared Magnetics Hall Thruster Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In the proposed Phase I program, Busek Co. will demonstrate an innovative methodology for clustering Hall thrusters into a high performance, very high power...

  14. "Hall mees" Linnateatris / Triin Sinissaar

    Index Scriptorium Estoniae

    Sinissaar, Triin

    1999-01-01

    Tallinn Linnateatri ja Raadioteatri ühislavastus "Hall mees" Gill Adamsi näidendi järgi, lavastaja Eero Spriit, osades Helene Vannari ja Väino Laes, kunstnik Kustav - Agu Püüman. Esietendus 22. okt

  15. "Hall mees" Linnateatris / Triin Sinissaar

    Index Scriptorium Estoniae

    Sinissaar, Triin

    1999-01-01

    Tallinn Linnateatri ja Raadioteatri ühislavastus "Hall mees" Gill Adamsi näidendi järgi, lavastaja Eero Spriit, osades Helene Vannari ja Väino Laes, kunstnik Kustav - Agu Püüman. Esietendus 22. okt

  16. Numerical bifurcation analysis of two coupled FitzHugh-Nagumo oscillators

    CERN Document Server

    Hoff, Anderson; Manchein, Cesar; Albuquerque, Holokx A

    2015-01-01

    The behavior of neurons can be modeled by the FitzHugh-Nagumo oscillator model, consisting of two nonlinear differential equations, which simulates the behavior of nerve impulse conduction through the neuronal membrane. In this work, we numerically study the dynamical behavior of two coupled FitzHugh-Nagumo oscillators. We consider unidirectional and bidirectional couplings, for which Lyapunov and isoperiodic diagrams were constructed calculating the Lyapunov exponents and the number of the local maxima of a variable in one period interval of the time-series, respectively. By numerical continuation method the bifurcation curves are also obtained for both couplings. The dynamics of the networks here investigated are presented in terms of the variation between the coupling strength of the oscillators and other parameters of the system. For the network of two oscillators unidirectionally coupled, the results show the existence of Arnold tongues, self-organized sequentially in a branch of a Stern-Brocot tree and ...

  17. The fusion of the imagination and the material universe: Hugh Hood, Flying a red kite (1962

    Directory of Open Access Journals (Sweden)

    Aleksander Kustec

    1999-12-01

    Full Text Available In the first weeks of January 1957 Hugh (John Blagdon Hood moved to Hartford, Connecticut, U. S. A, where he became Professor at Saint Joseph College. At the time Hood did not know that he was going to become one of Canada's greatest stylists and contemporary short story writers. Between January 1957 and March 1962, when he was going through a final selection o short stories for his first book, Flying a Red Kite (FRK, Hugh Hood wrote thirty-eight short stories and two novels (God Rest You Merry and Hungry Generations. The numbers show that Hood was an extremely productive writer in that period. From the thirty-eight stories he chose eleven for FRK, fourteen of them were published in subsequent collections, in various journals and short story anthologies, while thirteen of them have not been published yet.

  18. The 2016 Hughes Lecture: What's new in maternal morbidity and mortality?

    Science.gov (United States)

    Arendt, K W

    2016-05-01

    Each year, the Board of Directors of the Society for Obstetric Anesthesia and Perinatology selects an individual to review a given year's published obstetric anesthesiology literature. This individual then produces a syllabus of the year's most influential publications, delivers the Ostheimer Lecture at the Society's annual meeting, the Hughes Lecture at the following year's Sol Shnider meeting, and writes corresponding review articles. This 2016 Hughes Lecture review article focuses specifically on the 2014 publications that relate to maternal morbidity and mortality. It begins by discussing the 2014 research that was published on severe maternal morbidity and maternal mortality in developed countries. This is followed by a discussion of specific coexisting diseases and specific causes of severe maternal mortality. The review ends with a discussion of worldwide maternal mortality and the 2014 publications that examined the successes and the shortfalls in the work to make childbirth safe for women throughout the entire world.

  19. Periodismo ruso en el exilio: Alexánder Ivánovich Herzen (1812-1870

    Directory of Open Access Journals (Sweden)

    Miguel Vázquez Liñán

    2006-01-01

    Full Text Available El siguiente artículo se interesa por la actividad periodística de Alexánder Ivánovich Herzen (Moscú, 1812 – París, 1870 y reproduce un texto suyo de 1857, que sirvió como presentación de una de sus publicaciones más representativas: Kólokol (La Campana.The following article analyses the journalistic work of Alexander Ivanovich Herzen,and reproduce one of his articles of 1857, specifically the introducction to Kolokol (The Bell, one of his most representative publications.

  20. High T$_{c}$ superconductors and related transition metal oxides special contributions in honor of K. Alex Müller on the occasion of his 80th birthday

    CERN Document Server

    Bussmann-Holder, Annette

    2007-01-01

    This book containing 30 articles written by highly reputed experts is dedicated to K. Alex Müller on the occasion of his 80th birthday. The contributions reflect the major research areas of K. Alex Müller which he activated in high temperature superconductivity and phase transitions. They are theoretical as well as experimental ones and focus mainly on high temperature superconductivity. A smaller part deals with ferroelectricity and their applications. Also in this field there have recently been major break throughs experimentally as well as theoretically which will be addressed by the invited authors. During the scientific career of K. Alex Müller he made major advances in the understanding of ferroelectricity, which used to be his major research field. The discovery of superconductivity in cuprates for which he received together with J. Georg Bednorz the Nobel Prize in 1987 has not diminished his interest in this area, but has enlarged his activities considerably.

  1. General footage ISOLDE experimental hall HD

    CERN Multimedia

    2016-01-01

    Overview of the ISOLDE experimental hall. Equipment and experiments. Taken from the WITCH / EBIS platform: ISOLDE hall infrastructure, GHM line, LA1, LA2, LA0, central beamline, COLLAPS experiment, CRIS experiment, ISOLTRAP experiment, laser guidance from building 508 into the hall for laser spectroscopy COLLAPS and CRIS. Taken from the HIE ISOLDE shielding tunnel roof: ISOLDE hall infrastructure, WITCH experiment, VITO line, TAS experiment. General footage: High Tension room entrance and EBIS platform, staircases and passages in the experimental hall.

  2. Two-frequency self-oscillations in a FitzHugh-Nagumo neural network

    Science.gov (United States)

    Glyzin, S. D.; Kolesov, A. Yu.; Rozov, N. Kh.

    2017-01-01

    A new mathematical model of a one-dimensional array of FitzHugh-Nagumo neurons with resistive-inductive coupling between neighboring elements is proposed. The model relies on a chain of diffusively coupled three-dimensional systems of ordinary differential equations. It is shown that any finite number of coexisting stable invariant two-dimensional tori can be obtained in this chain by suitably increasing the number of its elements.

  3. Selected results from LLNL-Hughes RAR for West Coast Scotland Experiment 1991

    Energy Technology Data Exchange (ETDEWEB)

    Lehman, S K; Johnston, B; Twogood, R; Wieting, M; Yorkey, T; Robey, H [Lawrence Livermore National Lab., CA (United States); Whelan, D; Nagele, R [Hughes Aircraft Co., Los Angeles, CA (United States)

    1993-01-05

    The joint US -- UK 1991 West Coast Scotland Experiment (WCSEX) was held in two locations. From July 5 to 12, 1991, in Upper Loch Linnhe, and from July 18 to July 26, 1991, in the Sound of Sleat. The LLNL-Hughes team fielded a fully polarimetric X-band hill-side real aperture radar to collect internal wave wake data. We present here a sample data set of the best radar runs.

  4. Symmetric bursting behaviors in the generalized FitzHugh-Nagumo model.

    Science.gov (United States)

    Abbasian, A H; Fallah, H; Razvan, M R

    2013-08-01

    In the current paper, we have investigated the generalized FitzHugh-Nagumo model. We have shown that symmetric bursting behaviors of different types could be observed in this model with an appropriate recovery term. A modified version of this system is used to construct bursting activities. Furthermore, we have shown some numerical examples of delayed Hopf bifurcation and canard phenomenon in the symmetric bursting of super-Hopf/homoclinic type near its super-Hopf and homoclinic bifurcations, respectively.

  5. Young CAS biologist gets five-year grant from Howard Hughes Medical Institute

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    Dr. TANG Chun, an outstanding young biologist from the CAS Wuhan Institute of Physics and Mathematics (WIPM) was announced in January 2012 to have won the first International Early Career Award from Howard Hughes Medical Institute with a five-year grant totaling up to 650,000 US dollars. Dr. Tang is an expert in using novel nuclear magnetic resonance methods to study the behavior and function of proteins,

  6. 耦合的Fitz-Hugh-Nagumo模型的初边值问题

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    首先研究了具有耦合的 Fitz-Hugh-Nagumo 模型初值问题的渐近性. 其次,所对应的平衡态方程解的基本性态也将被讨论. 最后, 该模型的初边值问题古典解的最大吸引子的存在性将首次被证明.

  7. The Hughes Court and Radical Dissent: The Case of Dirk De Jonge and Angelo Herndon

    OpenAIRE

    Tushnet, Mark V.

    2012-01-01

    Scattered Supreme Court decisions in the early twentieth century dealt with the Constitution’s protection of freedom of speech. Radical dissent over United States participation in World War I and the nation’s intervention against the Bolshevik revolution in Russia led the Court to its first sustained engagement with free speech cases. By the time Chief Justice Hughes took the center chair, the national government largely had abandoned its pursuit of radical dissenters, some of whom played la...

  8. Percutaneous transhepatic venous embolization of pulmonary artery aneurysm in Hughes-Stovin syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kyung Ah; Kim, Man Deuk; Oh, Do Yun; Park, Pil Won [Bundang CHA General Hospital, Pochon CHA University, Seongnam (Korea, Republic of)

    2007-08-15

    Hughes-Stovin syndrome is an extremely rare entity. We present a case of a 42-year-old man, who developed deep vein and inferior vena cava (IVC) thrombosis, repeated internal bleeding and pulmonary artery aneurysms (PAAs). The patient presented with massive hemoptysis and with PAAs of a 2.5 cm maximum diameter. We describe the successful percutaneous transhepatic venous embolization of the PAAs due to occluded common vascular pathways to the pulmonary artery.

  9. A política de Hugh Dalton e o Bloqueio Económico (1940-1942)

    OpenAIRE

    Mariana Castro

    2015-01-01

    The World War II was a scenery of conflict and protagonists. Hugh Dalton was Minister of Economics of War between 1940 and 1942 in England. Highlighted by the measure in economic blockade the belligerents and neutral countries, proposing the control of smuggling through the prohibition of exports and imports with the German enemy, in other words ‘dry internally and externally “to weaken. This essay focuses on Hugh Dalton policy, leaving few clues and suggestions for further study ...

  10. Sheldon-Hall syndrome

    Directory of Open Access Journals (Sweden)

    Bamshad Michael J

    2009-03-01

    Full Text Available Abstract Sheldon-Hall syndrome (SHS is a rare multiple congenital contracture syndrome characterized by contractures of the distal joints of the limbs, triangular face, downslanting palpebral fissures, small mouth, and high arched palate. Epidemiological data for the prevalence of SHS are not available, but less than 100 cases have been reported in the literature. Other common clinical features of SHS include prominent nasolabial folds, high arched palate, attached earlobes, mild cervical webbing, short stature, severe camptodactyly, ulnar deviation, and vertical talus and/or talipes equinovarus. Typically, the contractures are most severe at birth and non-progressive. SHS is inherited in an autosomal dominant pattern but about half the cases are sporadic. Mutations in either MYH3, TNNI2, or TNNT3 have been found in about 50% of cases. These genes encode proteins of the contractile apparatus of fast twitch skeletal muscle fibers. The diagnosis of SHS is based on clinical criteria. Mutation analysis is useful to distinguish SHS from arthrogryposis syndromes with similar features (e.g. distal arthrogryposis 1 and Freeman-Sheldon syndrome. Prenatal diagnosis by ultrasonography is feasible at 18–24 weeks of gestation. If the family history is positive and the mutation is known in the family, prenatal molecular genetic diagnosis is possible. There is no specific therapy for SHS. However, patients benefit from early intervention with occupational and physical therapy, serial casting, and/or surgery. Life expectancy and cognitive abilities are normal.

  11. Iodine Hall Thruster

    Science.gov (United States)

    Szabo, James

    2015-01-01

    Iodine enables dramatic mass and cost savings for lunar and Mars cargo missions, including Earth escape and near-Earth space maneuvers. The demonstrated throttling ability of iodine is important for a singular thruster that might be called upon to propel a spacecraft from Earth to Mars or Venus. The ability to throttle efficiently is even more important for missions beyond Mars. In the Phase I project, Busek Company, Inc., tested an existing Hall thruster, the BHT-8000, on iodine propellant. The thruster was fed by a high-flow iodine feed system and supported by an existing Busek hollow cathode flowing xenon gas. The Phase I propellant feed system was evolved from a previously demonstrated laboratory feed system. Throttling of the thruster between 2 and 11 kW at 200 to 600 V was demonstrated. Testing showed that the efficiency of iodine fueled BHT-8000 is the same as with xenon, with iodine delivering a slightly higher thrust-to-power (T/P) ratio. In Phase II, a complete iodine-fueled system was developed, including the thruster, hollow cathode, and iodine propellant feed system. The nominal power of the Phase II system is 8 kW; however, it can be deeply throttled as well as clustered to much higher power levels. The technology also can be scaled to greater than 100 kW per thruster to support megawatt-class missions. The target thruster efficiency for the full-scale system is 65 percent at high specific impulse (Isp) (approximately 3,000 s) and 60 percent at high thrust (Isp approximately 2,000 s).

  12. Radical Democratic Education as Response to Two World Wars and a Contribution to World Peace: The Inspirational Work of Alex Bloom

    Science.gov (United States)

    Fielding, Michael

    2014-01-01

    A key contributor to the 1948 New Education Fellowship "The Teacher and World Peace" submission to UNESCO, Alex Bloom is one of the most remarkable pioneers of radical democratic education of the twentieth century. In many important respects, Bloom's internationally renowned work from 1945-55 at St George-in-the-East Secondary Modern…

  13. Radical Democratic Education as Response to Two World Wars and a Contribution to World Peace: The Inspirational Work of Alex Bloom

    Science.gov (United States)

    Fielding, Michael

    2014-01-01

    A key contributor to the 1948 New Education Fellowship "The Teacher and World Peace" submission to UNESCO, Alex Bloom is one of the most remarkable pioneers of radical democratic education of the twentieth century. In many important respects, Bloom's internationally renowned work from 1945-55 at St George-in-the-East Secondary Modern…

  14. Radical Democratic Education as Response to Two World Wars and a Contribution to World Peace: The Inspirational Work of Alex Bloom

    Science.gov (United States)

    Fielding, Michael

    2014-01-01

    A key contributor to the 1948 New Education Fellowship "The Teacher and World Peace" submission to UNESCO, Alex Bloom is one of the most remarkable pioneers of radical democratic education of the twentieth century. In many important respects, Bloom's internationally renowned work from 1945-55 at St George-in-the-East Secondary…

  15. Displacement ventilation in lecture halls

    OpenAIRE

    Egorov, Artem

    2013-01-01

    This thesis considers several important goals. The main purpose is to see how displacement ventilation sys-tem works in the lecture hall of M-building and compare obtained results with D2 and Indoor Climate Classi-fication. The second one is to analyze the function of the ventilation system. The last one is to realize when displacement ventilation is preferable to mixing ventilation. Analysis of the system was carried out with instruments from MUAS HVAC laboratory. In lecture hall were me...

  16. Bound values for Hall conductivity of heterogeneous medium under quantum Hall effect conditions

    Indian Academy of Sciences (India)

    V E Arkhincheev

    2008-02-01

    Bound values for Hall conductivity under quantum Hall effect (QHE) conditions in inhomogeneous medium has been studied. It is shown that bound values for Hall conductivity differ from bound values for metallic conductivity. This is due to the unusual character of current percolation under quantum Hall effect conditions.

  17. A "Queen of Hearts" trial of organ markets: why Scheper-Hughes's objections to markets in human organs fail.

    Science.gov (United States)

    Taylor, J S

    2007-04-01

    Nancy Scheper-Hughes is one of the most prominent critics of markets in human organs. Unfortunately, Scheper-Hughes rejects the view that markets should be used to solve the current (and chronic) shortage of transplant organs without engaging with the arguments in favour of them. Scheper-Hughes's rejection of such markets is of especial concern, given her influence over their future, for she holds, among other positions, the status of an adviser to the World Health Organization (Geneva) on issues related to global transplantation. Given her influence, it is important that Scheper-Hughes's moral condemnation of markets in human organs be subject to critical assessment. Such critical assessment, however, has not generally been forthcoming. A careful examination of Scheper-Hughes's anti-market stance shows that it is based on serious mischaracterisations of both the pro-market position and the medical and economic realities that underlie it. In this paper, the author will expose and correct these mischaracterisations and, in so doing, show that her objections to markets in human organs are unfounded.

  18. HARP model rotor test at the DNW. [Hughes Advanced Rotor Program

    Science.gov (United States)

    Dawson, Seth; Jordan, David; Smith, Charles; Ekins, James; Silverthorn, Lou

    1989-01-01

    Data from a test of a dynamically scaled model of the Hughes Advanced Rotor Program (HARP) bearingless model main rotor and 369K tail rotor are reported. The history of the HARP program and its goals are reviewed, and the main and tail rotor models are described. The test facilities and instrumentation are described, and wind tunnel test data are presented on hover, forward flight performance, and blade-vortex interaction. Performance data, acoustic data, and dynamic data from near field/far field and shear layer studies are presented.

  19. The spike timing precision of FitzHugh-Nagumo neuron network coupled by gap junctions

    Institute of Scientific and Technical Information of China (English)

    Zhang Su-Hua; Zhan Yong; Yu Hui; An Hai-Long; Zhao Tong-Jun

    2006-01-01

    It has been proved recently that the spike timing can play an important role in information transmission, so in this paper we develop a network with N-unit FitzHugh-Nagumo neurons coupled by gap junctions and discuss the dependence of the spike timing precision on synaptic coupling strength, the noise intensity and the size of the neuron ensemble. The calculated results show that the spike timing precision decreases as the noise intensity increases; and the ensemble spike timing precision increases with coupling strength increasing. The electric synapse coupling has a more important effect on the spike timing precision than the chemical synapse coupling.

  20. Markov chain Monte Carlo approach to parameter estimation in the FitzHugh-Nagumo model.

    Science.gov (United States)

    Jensen, Anders Chr; Ditlevsen, Susanne; Kessler, Mathieu; Papaspiliopoulos, Omiros

    2012-10-01

    Excitability is observed in a variety of natural systems, such as neuronal dynamics, cardiovascular tissues, or climate dynamics. The stochastic FitzHugh-Nagumo model is a prominent example representing an excitable system. To validate the practical use of a model, the first step is to estimate model parameters from experimental data. This is not an easy task because of the inherent nonlinearity necessary to produce the excitable dynamics, and because the two coordinates of the model are moving on different time scales. Here we propose a Bayesian framework for parameter estimation, which can handle multidimensional nonlinear diffusions with large time scale separation. The estimation method is illustrated on simulated data.

  1. Synchronization in heterogeneous FitzHugh-Nagumo networks with hierarchical architecture

    Science.gov (United States)

    Plotnikov, S. A.; Lehnert, J.; Fradkov, A. L.; Schöll, E.

    2016-07-01

    We study synchronization in heterogeneous FitzHugh-Nagumo networks. It is well known that heterogeneities in the nodes hinder synchronization when becoming too large. Here we develop a controller to counteract the impact of these heterogeneities. We first analyze the stability of the equilibrium point in a ring network of heterogeneous nodes. We then derive a sufficient condition for synchronization in the absence of control. Based on these results we derive the controller providing synchronization for parameter values where synchronization without control is absent. We demonstrate our results in networks with different topologies. Particular attention is given to hierarchical (fractal) topologies, which are relevant for the architecture of the brain.

  2. Hub-enhanced noise-sustained synchronization of an externally forced FitzHugh-Nagumo ring

    Science.gov (United States)

    Sánchez, Alejandro D.; Izús, Gonzalo G.; dell'Erba, Matías G.; Deza, Roberto R.

    2017-02-01

    A ring of FitzHugh-Nagumo units with antiphase coupling between their activator fields and submitted to a adiabatic harmonic subthreshold signal, is in turn globally coupled in electrical mode with the activator field of a hub. Noise sustained synchronization of neural activity with the signal is numerically observed, and theoretically characterized. The different dynamical regimes are elucidated using the concept of nonequilibrium potential, and the hub is found to promote network synchronization. The minimum noise intensities triggering the activation and synchronization processes are estimated in the framework of a three-neuron model.

  3. Synchronization and associative memory of FitzHugh-Nagumo neuronal networks with randomly distributed time delays

    Energy Technology Data Exchange (ETDEWEB)

    Peng, J H; Wu, Y J [School of Information Science and Engineering, East China University of Science and Technology, Shanghai 200237 (China); Yu, H J [Department of Mechanics, Shanghai Jiao Tong University, Shanghai 200240 (China)], E-mail: jhpeng@ecust.edu.cn

    2008-02-15

    Synchronization and associative memory in a neural network composed of the widely discussed FitzHugh-Nagumo neurons is investigated in this paper. Based on the reality of the microscopic biological structure in the neural system, the couplings among those neurons are accompanied with randomly distributed time delays which models the times needed for pulses propagating on the axons from the presynaptic neurons to the postsynaptic neurons. The memory is represented in the spatiotemporal firing pattern of the neurons, and the memory retrieval is accomplished with the fluctuations of the noise in the system.

  4. 空间离散Fitz-Hugh-Nagumo方程和双稳反应扩散方程组的渐近行为%Asymptotic Behavioui of Spatial Discretized Fitz-Hugh-Nagumo Equations and Bistable Reaction Diffusion Equations

    Institute of Scientific and Technical Information of China (English)

    黄建华; 路钢

    2000-01-01

    In this paper, we discuss the asymptotic behaviour of spatial disretization of Fitz-Hugh-Nagumo equations and bistable reaction diffusion equations with Neumamn boundary conditions, and the invariant regions, absorbing sets and global attractors are obtained and the estimation of Hausdorff dimension is given.%本文利用扰动方法,研究了Fitz-Hugh-Nagumo方程和双稳反应扩散方程在Neuman边值条件下空间离散后的渐近行为,证明了两个格微分方程组的不变区域、吸引集和整体吸引子的存在性,并给出了离散Fitz-Hugh-Nagumo方程的整体吸引子的Hausdorff维数估计.

  5. Berry curvature and various thermal Hall effects

    Science.gov (United States)

    Zhang, Lifa

    2016-10-01

    Applying the approach of semiclassical wave packet dynamics, we study various thermal Hall effects where carriers can be electron, phonon, magnon, etc. A general formula of thermal Hall conductivity is obtained to provide an essential physics for various thermal Hall effects, where the Berry phase effect manifests naturally. All the formulas of electron thermal Hall effect, phonon Hall effect, and magnon Hall effect can be directly reproduced from the general formula. It is also found that the Strěda formula can not be directly applied to the thermal Hall effects, where only the edge magnetization contributes to the Hall effects. Furthermore, we obtain a combined formula for anomalous Hall conductivity, thermal Hall electronic conductivity and thermal Hall conductivity for electron systems, where the Berry curvature is weighted by a different function. Finally, we discuss particle magnetization and its relation to angular momentum of the carrier, change of which could induce a mechanical rotation; and possible experiments for thermal Hall effect associated with a mechanical rotation are also proposed.

  6. The Other Hall Effect: College Board Physics

    Science.gov (United States)

    Sheppard, Keith; Gunning, Amanda M.

    2013-01-01

    Edwin Herbert Hall (1855-1938), discoverer of the Hall effect, was one of the first winners of the AAPT Oersted Medal for his contributions to the teaching of physics. While Hall's role in establishing laboratory work in high schools is widely acknowledged, his position as chair of the physics section of the Committee on College Entrance…

  7. A Gift for Reading Hall No. 1

    Science.gov (United States)

    MacWilliams, Bryon

    2009-01-01

    In this article, the author describes Reading Hall No. 1 of the Russian State Library. He was placed in the first reading hall in the mid-1990s, when the Russian government still honored Soviet traditions of granting certain privileges to certain foreigners. In the first hall, the rules are different. He can request as many books as he wants. He…

  8. Cleaner in Hall of Residence

    Science.gov (United States)

    Hotel and Catering Industry Training Board, Wembley (England).

    This syllabus is intended for the use of training personnel in drawing up training programs for cleaners in halls of residence. Its main objective is to produce fully trained cleaners, thereby maintaining and raising standards. The syllabus is divided into three sections: Introduction to Housekeeping Employees, and Tasks Performed by the Majority…

  9. Hall / Madle Mühlbach

    Index Scriptorium Estoniae

    Mühlbach, Madle

    2008-01-01

    Hallist värvusest interjööris, olles oma passiivsuses ja lakoonilisuses nii efektne, kui seda ilmestab mõni värvikam detail või neutraalne tasakaalustaja. Lk. 73 Eva Toome valitud halle esemeid müügivõrgust

  10. ATLAS Assembly Hall Open Day

    CERN Document Server

    Patrice Loiez

    2004-01-01

    To mark the 50th Anniversary of the founding of CERN, a day of tours, displays and presentations was held in October 2004. The assembly halls for the experiments that were waiting to be installed on the LHC, such as ATLAS shown here, were transformed into display areas and cafés.

  11. Montage of a Queering Deferred: Memory, Ownership, and Archival Silencing in the Rhetorical Biography of Langston Hughes.

    Science.gov (United States)

    Summers, Ian

    2016-01-01

    This article explores the intersection of archival privilege and heteronormative bias in the queering of Langston Hughes. Although it has been a common belief in LGBTQ communities that Hughes was gay, the battle over how his sexuality is defined in various biographical texts involves broader issues of dominant representations of sexuality and who gets to speak for those no longer able to speak for themselves. As such, the article examines the texts Looking for Langston and The Life of Langston Hughes as well as the discourses that surrounded both. Through this case study, it is apparent that there are still numerous cultural challenges posed to historical queering and that scholars must take an inventive approach to overcome them.

  12. Berta and Adelaide: the policy of consolidation of the royal power of Hugh of Arles

    Directory of Open Access Journals (Sweden)

    Giacomo Vignodelli

    2012-10-01

    Full Text Available Both twins dowers made up by Hugh of Provence, king of Italic Kingdom, for his betrothal with Berta and that of his son Lothair with Adelaide, have to be understood within the policy of strengthening the royal power led by the king in the Thirties of the Tenth century: the dowers are in fact the crown of that policy. The double dower constitution supplies the king of Italy the opportunity to reserve for himself (and for the new formed young royal couple a strong control of the center of the Po valley around Pavia and dismantles (for the benefit of the royal domain ducal bases of power in Tuscia. The analysis of the work of Hugh allows us to understand its policy towards the aristocracy and the mechanisms for the promotion of new families (Aleramici, Obertenghi, Canossa. The original documents of dower were kept in the monastery of St. Salvatore of Pavia, founded by Adelaide; this locations isn’t due to the goods endowment of the monastery but to their importance as instrument of political legitimacy of the new Ottonian royal family.

  13. Frequency Effect of Harmonic Noise on the FitzHugh-Nagumo Neuron Model

    Institute of Scientific and Technical Information of China (English)

    宋艳丽

    2011-01-01

    Using harmonic noise,the frequency effect of noise on the FitzHugh-Nagumo neuron model is investigated.The results show that the neuron has a resonance characteristic and responds strongly to the noise with a certain frequency at fixed power.Driven by the noise with this frequency,the train is most regular and the coefficient of variation R has a minimum.The imperfect synchronization takes place,which,however,is optimal only for noise with an appropriate frequency.It is shown that there exists coherence resonance related to frequency.%Using harmonic noise, the frequency effect of noise on the FitzHugh-Nagumo neuron model is investigated. The results show that the neuron has a resonance characteristic and responds strongly to the noise with a certain frequency at fixed power. Driven by the noise with this frequency, the train is most regular and the coefficient of variation R has a minimum. The imperfect synchronization takes place, which, however, is optimal only for noise with an appropriate frequency. It is shown that there exists coherence resonance related to frequency.

  14. Planar Hall effect bridge magnetic field sensors

    Science.gov (United States)

    Henriksen, A. D.; Dalslet, B. T.; Skieller, D. H.; Lee, K. H.; Okkels, F.; Hansen, M. F.

    2010-07-01

    Until now, the planar Hall effect has been studied in samples with cross-shaped Hall geometry. We demonstrate theoretically and experimentally that the planar Hall effect can be observed for an exchange-biased ferromagnetic material in a Wheatstone bridge topology and that the sensor signal can be significantly enhanced by a geometric factor. For the samples in the present study, we demonstrate an enhancement of the sensor output by a factor of about 100 compared to cross-shaped sensors. The presented construction opens a new design and application area of the planar Hall effect, which we term planar Hall effect bridge sensors.

  15. Optical Hall effect-model description: tutorial.

    Science.gov (United States)

    Schubert, Mathias; Kühne, Philipp; Darakchieva, Vanya; Hofmann, Tino

    2016-08-01

    The optical Hall effect is a physical phenomenon that describes the occurrence of magnetic-field-induced dielectric displacement at optical wavelengths, transverse and longitudinal to the incident electric field, and analogous to the static electrical Hall effect. The electrical Hall effect and certain cases of the optical Hall effect observations can be explained by extensions of the classic Drude model for the transport of electrons in metals. The optical Hall effect is most useful for characterization of electrical properties in semiconductors. Among many advantages, while the optical Hall effect dispenses with the need of electrical contacts, electrical material properties such as effective mass and mobility parameters, including their anisotropy as well as carrier type and density, can be determined from the optical Hall effect. Measurement of the optical Hall effect can be performed within the concept of generalized ellipsometry at an oblique angle of incidence. In this paper, we review and discuss physical model equations, which can be used to calculate the optical Hall effect in single- and multiple-layered structures of semiconductor materials. We define the optical Hall effect dielectric function tensor, demonstrate diagonalization approaches, and show requirements for the optical Hall effect tensor from energy conservation. We discuss both continuum and quantum approaches, and we provide a brief description of the generalized ellipsometry concept, the Mueller matrix calculus, and a 4×4 matrix algebra to calculate data accessible by experiment. In a follow-up paper, we will discuss strategies and approaches for experimental data acquisition and analysis.

  16. SÍNDROME DE FITZ-HUGH-CURTIS COMO HALLAZGO DURANTE CIRUGÍA GINECOLÓGICA

    OpenAIRE

    Ricci A,Paolo; Solà D,Vicente; Pardo S,Jack

    2009-01-01

    El síndrome de Fitz-Hugh-Curtis es una perihepatitis producida por una peritonitis secundaria al ascenso de bacterias, como resultado de una enfermedad inflamatoria pélvica. En la etapa crónica se pueden observar adherencias entre la pared abdominal y la superficie hepática, caracterizadas por la semejanza a "cuerdas de violín". Esta imagen es considerada criterio diagnóstico. Se presenta un caso de hallazgo de síndrome de Fitz-Hugh-Curtis, pesquisado durante la inspección rutinaria de la cav...

  17. SÍNDROME DE FITZ-HUGH-CURTIS COMO HALLAZGO DURANTE CIRUGÍA GINECOLÓGICA

    OpenAIRE

    Ricci A,Paolo; Solà D,Vicente; Pardo S,Jack

    2009-01-01

    El síndrome de Fitz-Hugh-Curtis es una perihepatitis producida por una peritonitis secundaria al ascenso de bacterias, como resultado de una enfermedad inflamatoria pélvica. En la etapa crónica se pueden observar adherencias entre la pared abdominal y la superficie hepática, caracterizadas por la semejanza a "cuerdas de violín". Esta imagen es considerada criterio diagnóstico. Se presenta un caso de hallazgo de síndrome de Fitz-Hugh-Curtis, pesquisado durante la inspección rutinaria de la cav...

  18. Electron dynamics in Hall thruster

    Science.gov (United States)

    Marini, Samuel; Pakter, Renato

    2015-11-01

    Hall thrusters are plasma engines those use an electromagnetic fields combination to confine electrons, generate and accelerate ions. Widely used by aerospace industries those thrusters stand out for its simple geometry, high specific impulse and low demand for electric power. Propulsion generated by those systems is due to acceleration of ions produced in an acceleration channel. The ions are generated by collision of electrons with propellant gas atoms. In this context, we can realize how important is characterizing the electronic dynamics. Using Hamiltonian formalism, we derive the electron motion equation in a simplified electromagnetic fields configuration observed in hall thrusters. We found conditions those must be satisfied by electromagnetic fields to have electronic confinement in acceleration channel. We present configurations of electromagnetic fields those maximize propellant gas ionization and thus make propulsion more efficient. This work was supported by CNPq.

  19. Symmetric functions and Hall polynomials

    CERN Document Server

    MacDonald, Ian Grant

    1998-01-01

    This reissued classic text is the acclaimed second edition of Professor Ian Macdonald's groundbreaking monograph on symmetric functions and Hall polynomials. The first edition was published in 1979, before being significantly expanded into the present edition in 1995. This text is widely regarded as the best source of information on Hall polynomials and what have come to be known as Macdonald polynomials, central to a number of key developments in mathematics and mathematical physics in the 21st century Macdonald polynomials gave rise to the subject of double affine Hecke algebras (or Cherednik algebras) important in representation theory. String theorists use Macdonald polynomials to attack the so-called AGT conjectures. Macdonald polynomials have been recently used to construct knot invariants. They are also a central tool for a theory of integrable stochastic models that have found a number of applications in probability, such as random matrices, directed polymers in random media, driven lattice gases, and...

  20. Fitz-Hugh-Curtis syndrome: abdominal pain in women of 26 years old Síndrome de Fitz-Hugh-Curtis: dolor abdominal en mujer de 26 años

    Directory of Open Access Journals (Sweden)

    Liseth Rivero-Sánchez

    2011-10-01

    Full Text Available Fitz-Hugh-Curtis syndrome is an inflammation of the liver capsule as a complication of pelvic inflammatory disease, whose most common etiologic agent is the C. trachomatis. The acute phase of the Fitz-Hugh-Curtis syndrome may present itself with pain in right upper abdomen, commonly confused with other hepatobiliary and gastrointestinal tract diseases. Definitive diagnosis is now possible with non-invasive techniques such as ultrasound, computed tomography, as well as techniques to isolate the responsible germ, available in most centers.El síndrome de Fitz-Hugh-Curtis es una inflamación de la cápsula hepática, como complicación de una enfermedad inflamatoria pélvica, cuyo agente etiológico más frecuente es la C. trachomatis. La fase aguda del síndrome de Fitz-Hugh-Curtis puede presentarse con dolor en cuadrante superior derecho del abdomen, confundiéndose comúnmente con otras enfermedades hepatobiliares y del tracto gastrointestinal. El diagnóstico definitivo es posible hoy en día por técnicas no invasivas como ecografía, tomografía computarizada, además de técnicas para el aislamiento del germen responsable disponibles en la mayoría de los centros.

  1. University receives $1.4 million science education award from Howard Hughes Medical Institute to support innovate undergraduate science education

    OpenAIRE

    Owczarski, Mark

    2010-01-01

    Virginia Tech was among 50 top research universities nationwide to receive a Precollege and Undergraduate Science Education Program award from the Howard Hughes Medical Institute (HHMI) that will be used to encourage university faculty to develop new ways to teach and inspire undergraduate students about science and research.

  2. Pretext, Context, Subtext: Textual Power in the Writing of Langston Hughes, Richard Wright, and Martin Luther King, Jr.

    Science.gov (United States)

    Bogumil, Mary L.; Molino, Michael R.

    1990-01-01

    Studies verbal pretexts, social subtexts, and interpretive contexts of works by Langston Hughes, Richard Wright, and Martin Luther King, Jr. Notes that cultural repression is propagated (and dispelled) in part through the power of language. Notes that these texts are relevant for teaching textual power in hopes of affecting social change. (RS)

  3. Theoretical analysis and control results for the FitzHugh-Nagumo equation

    Directory of Open Access Journals (Sweden)

    Marko Antonio Rojas-Medar

    2008-12-01

    Full Text Available In this paper we are concerned with some theoretical questions for the FitzHugh-Nagumo equation. First, we recall the system, we briefly explain the meaning of the variables and we present a simple proof of the existence and uniqueness of strong solution. We also consider an optimal control problem for this system. In this context, the goal is to determine how can we act on the system in order to get good properties. We prove the existence of optimal state-control pairs and, as an application of the Dubovitski-Milyoutin formalism, we deduce the corresponding optimality system. We also connect the optimal control problem with a controllability question and we construct a sequence of controls that produce solutions that converge strongly to desired states. This provides a strategy to make the system behave as desired. Finally, we present some open questions related to the control of this equation.

  4. The synchronization of FitzHugh-Nagumo neuron network coupled by gap junction

    Institute of Scientific and Technical Information of China (English)

    Zhan Yong; Zhang Su-Hua; Zhao Tong-Jun; An Hai-Long; Zhang Zhen-Dong; Han Ying-Rong; Liu Hui; Zhang Yu-Hong

    2008-01-01

    It is well known that the strong coupling can synchronize a network of nonlinear oscillators. Synchronization provides the basis of the remarkable computational performance of the brain. In this paper the FitzHugh-Nagumo neuron network is constructed. The dependence of the synchronization on the coupling strength, the noise intensity and the size of the neuron network has been discussed. The results indicate that the coupling among neurons works to improve the synchronization, and noise increases the neuron random dynamics and the local fluctuations; the larger the size of network, the worse the synchronization. The dependence of the synchronization on the strength of the electric synapse coupling and chemical synapse coupling has also been discussed, which proves that electric synapse coupling can enhance the synchronization of the neuron network largely.

  5. A correspondence between the models of Hodgkin-Huxley and FitzHugh-Nagumo revisited

    Science.gov (United States)

    Postnikov, Eugene B.; Titkova, Olga V.

    2016-11-01

    We present the discussion on the possibility to scale the classical dimensionless FitzHugh-Nagumo model of neuronal self-sustained oscillations to the range of variables corresponding to the results, which are provided by the biophysically relevant reduced two-dimensional Hodgkin-Huxley equations (the Rinzel model). It is shown that there exists a relatively simple choice of affine transformation, which results in time-dependent solutions, which reproduce with a high accuracy the time course of the recovery variable and the sharp onsets (intervals of fast motions on a phase trajectories) of the voltage spikes. As for the latter, the reasons for unavoidable difference are discussed as well as a necessity of taking into account applied current values during such a scaling procedure.

  6. Stochastic bifurcation in FitzHugh Nagumo ensembles subjected to additive and/or multiplicative noises

    Science.gov (United States)

    Hasegawa, Hideo

    2008-02-01

    We have studied the dynamical properties of finite N-unit FitzHugh-Nagumo (FN) ensembles subjected to additive and/or multiplicative noises, reformulating the augmented moment method (AMM) with the Fokker-Planck equation (FPE) method [H. Hasegawa, J. Phys. Soc. Japan 75 (2006) 033001]. In the AMM, original 2N-dimensional stochastic equations are transformed to eight-dimensional deterministic ones, and the dynamics is described in terms of averages and fluctuations of local and global variables. The stochastic bifurcation is discussed by a linear stability analysis of the deterministic AMM equations. The bifurcation transition diagram of multiplicative noise is rather different from that of additive noise: the former has the wider oscillating region than the latter. The synchronization in globally-coupled FN ensembles is also investigated. Results of the AMM are in good agreement with those of direct simulations (DSs).

  7. Phase Propagations in a Coupled Oscillator-Excitor System of FitzHugh-Nagumo Models

    Institute of Scientific and Technical Information of China (English)

    ZHOU Lu-Qun; OUYANG Qi

    2006-01-01

    @@ A one-dimensional array of 2N + 1 automata with FitzHugh-Nagumo dynamics, in which one is set to be oscillatory and the others are excitable, is investigated with bi-directional interactions. We find that 1 : 1 rhythm propagation in the array depends on the appropriate couple strength and the excitability of the system. On the two sides of the 1: 1 rhythm area in parameter space, two different kinds of dynamical behaviour of the pacemaker, i.e. phase-locking phenomena and canard-like phenomena, are shown. The latter is found in company with chaotic pattern and period doubling bifurcation. When the coupling strength is larger than a critical value,the whole system ends to a steady state.

  8. Fitz-Hugh-Curtis syndrome lacking typical characteristics of pelvic inflammatory disease.

    Science.gov (United States)

    Mitaka, Hayato; Kitazono, Hidetaka; Deshpande, Gautam A; Hiraoka, Eiji

    2016-06-22

    A 23-year-old Japanese woman, previously a commercial sex worker, presented with a 2-day history of right upper quadrant (RUQ) abdominal pain, worse on deep inspiration. She had noticed increased vaginal discharge 2 months earlier and had developed dull, lower abdominal pain 3 weeks prior to presentation. Although pelvic examination and transvaginal ultrasonography revealed neither a tubal nor ovarian pathology, abdominal CT scan with contrast demonstrated early enhancement of the hepatic capsule, a finding pathognomonic for Fitz-Hugh-Curtis syndrome (FHCS). Cervical discharge PCR assay confirmed Chlamydia trachomatis infection. This case highlights that normal gynaecological evaluation may be insufficient to rule out FHCS, for which physicians should have a high index of suspicion when seeing any woman of reproductive age with RUQ pain. 2016 BMJ Publishing Group Ltd.

  9. Identification of the FitzHugh-Nagumo Model Dynamics via Deterministic Learning

    Science.gov (United States)

    Dong, Xunde; Wang, Cong

    In this paper, a new method is proposed for the identification of the FitzHugh-Nagumo (FHN) model dynamics via deterministic learning. The FHN model is a classic and simple model for studying spiral waves in excitable media, such as the cardiac tissue, biological neural networks. Firstly, the FHN model described by partial differential equations (PDEs) is transformed into a set of ordinary differential equations (ODEs) by using finite difference method. Secondly, the dynamics of the ODEs is identified using the deterministic learning theory. It is shown that, for the spiral waves generated by the FHN model, the dynamics underlying the recurrent trajectory corresponding to any spatial point can be accurately identified by using the proposed approach. Numerical experiments are included to demonstrate the effectiveness of the proposed method.

  10. The African-American grandmother in autobiographical works by Frederick Douglass, Langston Hughes, and Maya Angelou.

    Science.gov (United States)

    Hill-Lubin, M A

    1991-01-01

    Using the autobiographies of Frederick Douglass, Langston Hughes, and Maya Angelou, this article demonstrates that the portrait of the African-American grandmother is one of action, involvement, hope, and dignity. In examining the works, we observe her functioning in three areas: as the preserver and most tenacious survivor of the African extended family; second, as repository and distributor of the family history, wisdom, and black lore; this role places her at the foundation of the Black, oral and written, literary and creative traditions; and third, as the retainer and transmitter of values and ideals that support and enhance her humanity, her family, and her community. This function emphasizes her spirituality. It is suggested that the grandmother, having played an important role in the growth, development, and artistic flowering of the autobiographer, can become a model and source of empowerment for future generations.

  11. Spin Hall effect by surface roughness

    KAUST Repository

    Zhou, Lingjun

    2015-01-08

    The spin Hall and its inverse effects, driven by the spin orbit interaction, provide an interconversion mechanism between spin and charge currents. Since the spin Hall effect generates and manipulates spin current electrically, to achieve a large effect is becoming an important topic in both academia and industries. So far, materials with heavy elements carrying a strong spin orbit interaction, provide the only option. We propose here a new mechanism, using the surface roughness in ultrathin films, to enhance the spin Hall effect without heavy elements. Our analysis based on Cu and Al thin films suggests that surface roughness is capable of driving a spin Hall angle that is comparable to that in bulk Au. We also demonstrate that the spin Hall effect induced by surface roughness subscribes only to the side-jump contribution but not the skew scattering. The paradigm proposed in this paper provides the second, not if only, alternative to generate a sizable spin Hall effect.

  12. Observation of the Zero Hall Plateau in a Quantum Anomalous Hall Insulator

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Yang; Feng, Xiao; Ou, Yunbo; Wang, Jing; Liu, Chang; Zhang, Liguo; Zhao, Dongyang; Jiang, Gaoyuan; Zhang, Shou-Cheng; He, Ke; Ma, Xucun; Xue, Qi-Kun; Wang, Yayu

    2015-09-16

    We report experimental investigations on the quantum phase transition between the two opposite Hall plateaus of a quantum anomalous Hall insulator. We observe a well-defined plateau with zero Hall conductivity over a range of magnetic field around coercivity when the magnetization reverses. The features of the zero Hall plateau are shown to be closely related to that of the quantum anomalous Hall effect, but its temperature evolution exhibits a significant difference from the network model for a conventional quantum Hall plateau transition. We propose that the chiral edge states residing at the magnetic domain boundaries, which are unique to a quantum anomalous Hall insulator, are responsible for the novel features of the zero Hall plateau.

  13. Low-Voltage Hall Thruster Mode Transitions

    Science.gov (United States)

    2014-06-01

    Technical Paper 3. DATES COVERED (From - To) June 2014- July 2014 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER In-House Low-Voltage Hall Thruster Mode...ABSTRACT Past investigations of the 6kW-class H6 Hall thruster during low-voltage operation revealed two operating modes, corresponding to the...topologies were characterized for the H6 Hall thruster from 100V to 200V discharge, with variation in cathode flow fraction, cathode position inside and

  14. Listening to the acoustics in concert halls

    Science.gov (United States)

    Beranek, Leo L.; Griesinger, David

    2004-05-01

    How does acoustics affect the symphonic music performed in a concert hall? The lecture begins with an illustrated discussion of the architectural features that influence the acoustics. Boston Symphony Hall, which was built in 1900 when only one facet of architectural design was known, now rates as one of the world's great halls. How this occurred will be presented. Music is composed with some acoustical environment in mind and this varies with time from the Baroque to the Romantic to the Modern musical period. Conductors vary their interpretation according to the hall they are in. Well-traveled listeners and music critics have favorite halls. The lecture then presents a list of 58 halls rank ordered according to their acoustical quality based on interviews of music critics and conductors. Modern acoustical measurements made in these halls are compared with their rankings. Music recordings will be presented that demonstrate how halls sound that have different measured acoustical parameters. Photographs of a number of recently built halls are shown as examples of how these known acoustical factors have been incorporated into architectural design.

  15. Hall probes: physics and application to magnetometry

    CERN Document Server

    Sanfilippo, S

    2010-01-01

    This lecture aims to present an overview of the properties of Hall effect devices. Descriptions of the Hall phenomenon, a review of the Hall effect device characteristics and of the various types of probes are presented. Particular attention is paid to the recent development of three-axis sensors and the related techniques to cancel the offsets and the planar Hall effect. The lecture introduces the delicate problem of the calibration of a three-dimensional sensor and ends with a section devoted to magnetic measurements in conventional beam line magnets and undulators.

  16. DEVELOPMENT OF IMPROVED HALL EFFECT SENSORS.

    Science.gov (United States)

    HALL EFFECT , MAGNETOMETERS, GAIN, SENSITIVITY, MAGNETIC FIELDS, DETECTION, ELECTROMAGNETIC PROBES, WEIGHT, VOLUME, BATTERY COMPONENTS, INDIUM ALLOYS, ANTIMONY ALLOYS, FERRITES, MANPORTABLE EQUIPMENT.

  17. AN A. C. HALL EFFECT GAUSSMETER,

    Science.gov (United States)

    MEASURING INSTRUMENTS, MEASURING INSTRUMENTS, HALL EFFECT , MAGNETOMETERS, MEASUREMENT, GENERATORS, CIRCUITS, ALTERNATING CURRENT, GERMANIUM, SEMICONDUCTOR DIODES, GALVANOMETERS, VOLTAGE, DIRECT CURRENT, MAGNETIC FIELDS.

  18. Lectures on the Quantum Hall Effect

    CERN Document Server

    Tong, David

    2016-01-01

    The purpose of these lectures is to describe the basic theoretical structures underlying the rich and beautiful physics of the quantum Hall effect. The focus is on the interplay between microscopic wavefunctions, long-distance effective Chern-Simons theories, and the modes which live on the boundary. The notes are aimed at graduate students in any discipline where $\\hbar=1$. A working knowledge of quantum field theory is assumed. Contents: 1. The Basics (Landau levels and Berry phase). 2. The Integer Quantum Hall Effect. 3. The Fractional Quantum Hall Effect. 4. Non-Abelian Quantum Hall States. 5. Chern-Simons Theories. 6. Edge Modes.

  19. Anomalous Hall effect in polycrystalline Ni films

    KAUST Repository

    Guo, Zaibing

    2012-02-01

    We systematically studied the anomalous Hall effect in a series of polycrystalline Ni films with thickness ranging from 4 to 200 nm. It is found that both the longitudinal and anomalous Hall resistivity increased greatly as film thickness decreased. This enhancement should be related to the surface scattering. In the ultrathin films (46 nm thick), weak localization corrections to anomalous Hall conductivity were studied. The granular model, taking into account the dominated intergranular tunneling, has been employed to explain this phenomenon, which can explain the weak dependence of anomalous Hall resistivity on longitudinal resistivity as well. © 2011 Elsevier Ltd. All rights reserved.

  20. Automated Micro Hall Effect measurements

    DEFF Research Database (Denmark)

    Petersen, Dirch Hjorth; Henrichsen, Henrik Hartmann; Lin, Rong

    2014-01-01

    With increasing complexity of processes and variety of materials used for semiconductor devices, stringent control of the electronic properties is becoming ever more relevant. Collinear micro four-point probe (M4PP) based measurement systems have become high-end metrology methods for characteriza......With increasing complexity of processes and variety of materials used for semiconductor devices, stringent control of the electronic properties is becoming ever more relevant. Collinear micro four-point probe (M4PP) based measurement systems have become high-end metrology methods...... for characterization and monitoring of sheet resistance as well as sheet carrier density and mobility via the Micro Hall Effect (MHE) method....

  1. Temperature Gradient in Hall Thrusters

    Energy Technology Data Exchange (ETDEWEB)

    D. Staack; Y. Raitses; N.J. Fisch

    2003-11-24

    Plasma potentials and electron temperatures were deduced from emissive and cold floating probe measurements in a 2 kW Hall thruster, operated in the discharge voltage range of 200-400 V. An almost linear dependence of the electron temperature on the plasma potential was observed in the acceleration region of the thruster both inside and outside the thruster. This result calls into question whether secondary electron emission from the ceramic channel walls plays a significant role in electron energy balance. The proportionality factor between the axial electron temperature gradient and the electric field is significantly smaller than might be expected by models employing Ohmic heating of electrons.

  2. L’oeuvre artistique d’Alex Fleming: illustration du corps comme espace de production de significations culturelles et politiques

    Directory of Open Access Journals (Sweden)

    Fernando do Nascimento Gonçalves

    2009-10-01

    Full Text Available Nombre d’artistes s’occupent du corps en tant que dispositif de production de significations sociales (le corps habillé, docile, masculin, féminin, citoyen, étranger, esthétisé, sain, malade, monstrueux, etc.. Le plasticien brésilien Alex Flemming se situe dans ce courant. Son travail se caractérise par une profusion d’installations, sculptures et photographies où le corps devient le médium de la problématisation du politique, de la mémoire collective et de l’identité dans la culture occidentale contemporaine. Cet article se propose d’analyser comment, chez l’artiste, le corps est construit en tant qu’élément d’analyse de phénomènes tels que la «dépersonnalisation» de l’individu, la production des identités culturelles et de la violence dans les conflits internationaux. Il s’intéressera particulièrement à montrer comment le corps pourrait aujourd’hui mettre en évidence les dimensions «subjectives» de tels phénomènes ainsi que les relations de pouvoir «moins visibles» qu’elles impliquent.

  3. Cyberpuppets:The Marxist discourse and the collision between the public and private sphere in Alex Rivera’s films

    Directory of Open Access Journals (Sweden)

    Alfredo Suppia

    2012-07-01

    Full Text Available The aim of this paper is to analyze a possible Marxist discourse and how technologies of telepresence favor the collision of the public and private sphere in Alex Rivera’s films Why Cybraceros? and Sleep Dealer. Why Cybraceros? is a mockumentary based on the American Bracero Program, which was put in practice during World War II. This short film satirizes the 1940s American policy for foreign workers with the ideals of homeoffice working and remote technology, devising a tragicomic dystopia in which Mexican labourers are exploited in their own country. Sleep Dealer enhances this dystopia in a 2008 science fiction feature film. Regarded as a kind of “Latin American Matrix”, Sleep Dealer’s speculative dystopia sets further debates in terms of alienation, reification, global capital, the impact of technology on everyday life, and social relations mediated by technologies of telepresence. Thus, Sleep Dealer’s dystopia proposes the implosion of the individual, private sphere, in as much as the working time invades the personal time for intimacy, leisure and cultural practices. Memories can be exploited as merchandise, whereas misery and violence are sold as mass entertainment

  4. Open Sores of a Republic: Injustice and Poverty as Motifs in Alex La Guma’s First Three Novels

    Directory of Open Access Journals (Sweden)

    OGBEIDE, O. Victor

    2013-11-01

    Full Text Available This paper examines injustice and poverty as motifs in Alex La Guma’s first three novels. A motif is a recurrent formal element in a work of art. The foundation of apartheid is injustice which often leads to massive poverty on the part of the non-white community whose members are hapless victims of marginalization and disfranchisement in the Republic of South Africa. The prevalence of the twin forces of injustice and poverty in apartheid South Africa which La Guma artistically portrays in his first three novels confers on them the status of a motif. This, in itself, is a function of the novelist’s deference to realism and artistic relevance. The paper discovers that the unrelenting travesty of justice and the prevalence of destitution which describe so many unsavoury scenes in the novels in focus are due to the non-whites’ lack of meaningful political consciousness which itself is a function of the racist government’s stamp on oppositional discourse. It is this vacuum that the puny and ineffective pockets of individual acts of courage attempt to fill in the three novels to no avail. Keywords: injustice, poverty, motifs, apartheid, marginalization, realism

  5. “My big statement”: art, political experience and the quest for identity in Alex Kuo's Chinese Opera

    Directory of Open Access Journals (Sweden)

    Fulvia Sarnelli

    2015-11-01

    Full Text Available Il saggio considera l'esperienza politica degli intellettuali cinesi e americani in Chinese Opera (1998, romanzo breve dello scrittore americano di discendenza cinese Alex Kuo. Il suo protagonista, compiendo un viaggio dagli Stati Uniti alla Cina nei mesi immediatamente precedenti alle dimostrazioni di piazza Tiananmen, intraprende un cammino alla ricerca della sua storia familiare, e delle ragioni che hanno spinto il padre all'esilio. Intellettuale e musicista, a cavallo tra due realtà di attivismo politico che hanno esercitato il loro peso nel definire o nello smantellare, a seconda delle prospettive, proprio i concetti di appartenenza, il protagonista sceglie e fa proprio l'impegno sul piano transnazionale, ma a partire da una consolidata quanto rivendicata consapevolezza della propria individualità. La letteratura e l'arte sono il punto focale in grado di esprimere una tensione tra l'individuo e la collettività che ritorna con una declinazione diversa in entrambi i sistemi socio-politici. Il romanzo, dunque, propone un soggetto politicizzato ma non contenibile all'interno di alcuna coordinata discorsiva pre-scritta. A sua volta, il discorso politico nel testo letterario, costruito nel senso della double critique di Khatibi, intreccia la dimensione pubblica e privata dell'intellettuale con le significazioni etniche, nazionali e transnazionali.

  6. A Holographic Quantum Hall Ferromagnet

    CERN Document Server

    Kristjansen, C; Semenoff, G W

    2013-01-01

    A detailed numerical study of a recent proposal for exotic states of the D3-probe D5 brane system with charge density and an external magnetic field is presented. The state has a large number of coincident D5 branes blowing up to a D7 brane in the presence of the worldvolume electric and magnetic fields which are necessary to construct the holographic state. Numerical solutions have shown that these states can compete with the the previously known chiral symmetry breaking and maximally symmetric phases of the D3-D5 system. Moreover, at integer filling fractions, they are incompressible with integer quantized Hall conductivities. In the dual superconformal defect field theory, these solutions correspond to states which break the chiral and global flavor symmetries spontaneously. The region of the temperature-density plane where the D7 brane has lower energy than the other known D5 brane solutions is identified. A hypothesis for the structure of states with filling fraction and Hall conductivity greater than on...

  7. Infrared Hall Conductivity in Graphene

    Science.gov (United States)

    Ellis, C. T.; Kim, M.-H.; Wu, T.; Sambandamurthy, G.; Cerne, J.; Lee, V.; Banerjee, S.

    2009-03-01

    Among the many different techniques which have revealed graphene's remarkable properties, infrared conductivity (σxx) (Jiang, PRL 2007) and the DC Hall effect (Novoselov, Nature 2005; Zhang, Nature 2005; Zhang, PRL 2006) have provided new insights into this material. In our study we determine the infrared Hall conductivity (σxy) for graphene in the 120-1000 meV range at temperatures down to 7K and magnetic fields up to 7T using Faraday measurements. Unlike σxx, which measures the sum of the optical responses for left and right circularly polarized light, σxy measures the difference and therefore is sensitive to small changes in symmetry. We compare graphene samples that are prepared using several methods, including cleaving from parent materials such as highly ordered pyrolytic graphite, as well as sonication-assisted solution-phase exfoliation of natural flake graphite powder. The films are then deposited onto Si/SiO2 substrates for infrared measurements. This work is supported by the NSF-CAREER-DMR0449899, also GS and SB thank the UB-IRDF for financial support.

  8. Hugh E. Huxley: cambiando el paradigma de la contracción muscular, desde dentro. [Hugh E. Huxley: changing from inside the paradigm of muscle contraction].

    Directory of Open Access Journals (Sweden)

    Adolfo Araci

    2014-04-01

    Full Text Available Desde un punto de vista físico se puede entender la fibra muscular como un motor, es decir, un sistema capaz de transformar la energía química en energía mecánica, que se utiliza para realizar un trabajo. Por lo tanto, para entender cómo ocurre dicho proceso de transformación es necesario conocer la ultraestructura de la fibra muscular. Esta es, sin duda, la principal aportación al acervo científico del recientemente fallecido Hugh Emor Huxley (1924-2013. Huxley se graduó en Física en el Christ’s College de Cambdrige, tras ver interrumpidos temporalmente sus estudios por su dedicación como operario de radar de la Royal Air Force entre 1943 y 1947, durante la Segunda Guerra Mundial (Pollard y Goldman, 2013; Spudich, 2013. Tras su graduación se incorporó como el primer estudiante de doctorado a una unidad de nueva creación del Medical Research Council, el “Laboratorio de Biología Molecular”, dirigida por Max Perutz y John Kendrew, siendo este último el director de sus tesis doctoral, que fue defendida en 1952 (Spudich, 2013. El uso de la técnicas de difracción de rayos X, que permitían el estudio en niveles de resolución inalcanzables con las técnicas microscópicas del momento, y su aplicación a la descripción de la ultraestructura muscular, fueron el objeto de su tesis doctoral, para el desarrollo de la cual diseñó y construyó sus propios instrumentos. El esclarecimiento de los aspectos estructurales implicados en la contracción muscular se convirtió desde entonces en la pregunta central de su biografía científica.

  9. Library rooms or Library halls

    Directory of Open Access Journals (Sweden)

    Alfredo Serrai

    2013-12-01

    Full Text Available Library Halls, understood as Renaissance and Baroque architectural creations, along with the furnishings and decorations, accomplish a cognitive task and serve to transmit knowledge. The design of these spaces based on the idea that they should reflect the merits and content of the collections housed within them, in order to prepare the mind of the reader to respect and admire the volumes. In accordance with this principle, in the fifteenth century library rooms had a basilican shape, with two or three naves, like churches, reflecting thus the spiritual value of the books contained there. Next to that inspiring function, library rooms had also the task of representing the entire logical and conceptual universe of human knowledge in a figurative way, including for this purpose also the and Kunst- und Wunderkammern, namely the collections of natural, artficial objects, and works of art. The importance of library rooms and their function was understood already in the early decades of the seventeenth century, as underlined in the treatise, Musei sive Bibliothecae tam privatae quam publicae Extructio, Instructio, Cura, Usus, written by the Jesuit Claude Clément and published in 1635. Almost the entire volume is dedicated to the decoration and ornamentation of the Saloni, and the function of the library is identified exclusively with the preservation and decoration of the collection, neglecting more specifically bibliographic aspects or those connected to library science. The architectural structure of the Saloni was destined to change in relation to two factors, namely the form of books, and the sources of light. As a consequence, from the end of the sixteenth century – or perhaps even before if one considers the fragments of the Library of Urbino belonging to Federico da Montefeltro – shelves and cabinets have been placed no longer in the center of the room, but were set against the walls. This new disposition of the furniture, surmounted by

  10. Training Top 10 Hall of Fame

    Science.gov (United States)

    Training, 2012

    2012-01-01

    Microsoft Corporation and SCC Soft Computer are the newest inductees into the Training Top 10 Hall of Fame, joining the ranks of the 11 companies named to the hall since its inception in 2008 (Wyeth Pharmaceuticals subsequently was acquired by Pfizer Inc. in 2009). These 11 companies held Top 10 spots in the Training Top 50, Top 100, and now Top…

  11. 20th Annual Residence Hall Construction Report

    Science.gov (United States)

    Agron, Joe

    2009-01-01

    Even in difficult economic times, colleges and universities continue to invest in residence hall construction projects as a way to attract new students and keep existing ones on campus. According to data from "American School & University"'s 20th annual Residence Hall Construction Report, the median new project completed in 2008 was…

  12. 19th Annual Residence Hall Construction Report

    Science.gov (United States)

    Agron, Joe

    2008-01-01

    The construction of residence hall facilities at colleges and universities continues to be strong, as institutions scramble to meet the housing needs and varied demands of a growing student population. This article presents data collected from 39 new residence hall projects completed in 2007. According to American School & University's 19th…

  13. Hall effect accompanying a static skin effect

    Energy Technology Data Exchange (ETDEWEB)

    Volkenshtein, N.V.; Marchenkov, V.V.; Startsev, V.E.; Cherepanov, A.N.; Glin' skii, M.

    1985-05-10

    The Hall effect and the magnetoresistance of tungsten single crystals with rho/sub 293K//rho/sub 4.2K/ = 80 000 have been measured at 4.2 K in magnetic fields up to 150 kOe. The results reveal that a static skin effect gives rise to an anomalously pronounced increase in the Hall coefficient.

  14. Acoustical parameters in concert hall acoustics

    Institute of Scientific and Technical Information of China (English)

    LIU Ke; ZHOU Qijun

    2003-01-01

    Professor Beranek talked about the sound qualities of concert hall. The 58 famousconcert halls in the world were graded according to the subjective comparison from the profes-sional musicians and music lovers. Six measurable objective parameters were proposed. Theranking according to these parameters were presented.

  15. The Scientific Humanism of G. Stanley Hall

    Science.gov (United States)

    Meyer, Donald H.

    1971-01-01

    This paper presents the humanistic psychology of the pioneer American psychologist Granville Stanley Hall (1844-1924), examining Hall's effort to develop a system of psychology that is at once rigorously scientific and, simultaneously, capable of verifying essential human values. (Author)

  16. Star Formation and the Hall Effect

    CERN Document Server

    Braiding, Catherine

    2011-01-01

    Magnetic fields play an important role in star formation by regulating the removal of angular momentum from collapsing molecular cloud cores. Hall diffusion is known to be important to the magnetic field behaviour at many of the intermediate densities and field strengths encountered during the gravitational collapse of molecular cloud cores into protostars, and yet its role in the star formation process is not well-studied. This thesis describes a semianalytic self-similar model of the collapse of rotating isothermal molecular cloud cores with both Hall and ambipolar diffusion, presenting similarity solutions that demonstrate that the Hall effect has a profound influence on the dynamics of collapse. ... Hall diffusion also determines the strength of the magnetic diffusion and centrifugal shocks that bound the pseudo and rotationally-supported discs, and can introduce subshocks that further slow accretion onto the protostar. In cores that are not initially rotating Hall diffusion can even induce rotation, whic...

  17. The Long-Time Behavior of Legendre Spectral Approximation to Fitz-Hugh-Nagumo Equation%Fitz-Hugh-Nagumo方程Legendre谱逼近的长时间性态

    Institute of Scientific and Technical Information of China (English)

    张伟斌

    2005-01-01

    利用Legendre谱方法对Fitz-Hugh-Nagumo方程在空间方向半离散,得到了其近似解的误差估计,并且证明了近似整体吸引子的存在性和上半连续性,从而为研究该方程的长时间行为提供了一个有效的算法.

  18. Delcam立足中国再创辉煌--访Delcam公司总经理Hugh Humphreys

    Institute of Scientific and Technical Information of China (English)

    王崇民; 朱旭

    2004-01-01

    @@ 进入2004年以来,Delcam(中国)公司表现得非常活跃,在进行一系列人事调整之后,西安办事处正式挂牌,紧接着又将北京迪勒克斯科技发展有限公司纳入旗下,使其成为Delcam(中国)华北地区增值经销商,在签约仪式上,记者见到了专程从英国前来祝贺的Delcam PLC集团公司总经理HughHumphreys先生,开朗、风趣的HughHumphreys先生非常愉快地接受了本刊记者的采访.

  19. 2002 Report to Congress: Evaluating the Consensus Best Practices Developed through the Howard Hughes Medical Institute’s Collaborative Hazardous Waste Management Demonstration Project

    Science.gov (United States)

    This report discusses a collaborative project initiated by the Howard Hughes Medical Institute (HHMI) to establish and evaluate a performance-based approach to management of hazardous wastes in the laboratories of academic research institutions.

  20. New type of chimera structures in a ring of bistable FitzHugh-Nagumo oscillators with nonlocal interaction

    Science.gov (United States)

    Shepelev, I. A.; Vadivasova, T. E.; Bukh, A. V.; Strelkova, G. I.; Anishchenko, V. S.

    2017-04-01

    We study the spatiotemporal dynamics of a ring of nonlocally coupled FitzHugh-Nagumo oscillators in the bistable regime. A new type of chimera patterns has been found in the noise-free network and when isolated elements do not oscillate. The region of existence of these structures has been explored when the coupling range and the coupling strength between the network elements are varied.

  1. Stuart Hall: An Organic Intellectual

    Directory of Open Access Journals (Sweden)

    Johanna Fernández Castro

    2017-01-01

    Full Text Available Stuart Hall (3 February 1932 – 10 February 2014 is acknowledged as one of the founding figures of British Cultural Studies. His extensive academic work on topics such as race, ethnicity and identity reflects his own position as a diasporic intellectual. His contribution to the study of popular culture is determined by the importance of his political character in every social act, his non-deterministic view of Marxism, and is especially determined by his insistence on playing an active role beyond academia in order to contribute to the transformation of hegemonic structures. The following biography aims to give a focused view of his personal history and its direct influence on his key theoretical reflections.

  2. Lian-Sheng Ma, Editor-in-Chief of WJG, warmly meets Professor Hugh J Freeman from the University of British Columbia

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Lian-Sheng Ma, Editor-in-Chief of World Journal of Gastroenterology (WJG), warmly met Professor Hugh J Freeman from the University of British Columbia at Peninsula Hotel in Beijing on August 28, 2007. Professor Hugh J Freeman gave much helpful advice toward the further development of WJG. He will serve as series editor for a new column called OBSERVER which will start in WJG in 2008.

  3. Dynamical System Approach for Edge Detection Using Coupled FitzHugh-Nagumo Neurons.

    Science.gov (United States)

    Li, Shaobai; Dasmahapatra, Srinandan; Maharatna, Koushik

    2015-12-01

    The prospect of emulating the impressive computational capabilities of biological systems has led to considerable interest in the design of analog circuits that are potentially implementable in very large scale integration CMOS technology and are guided by biologically motivated models. For example, simple image processing tasks, such as the detection of edges in binary and grayscale images, have been performed by networks of FitzHugh-Nagumo-type neurons using the reaction-diffusion models. However, in these studies, the one-to-one mapping of image pixels to component neurons makes the size of the network a critical factor in any such implementation. In this paper, we develop a simplified version of the employed reaction-diffusion model in three steps. In the first step, we perform a detailed study to locate this threshold using continuous Lyapunov exponents from dynamical system theory. Furthermore, we render the diffusion in the system to be anisotropic, with the degree of anisotropy being set by the gradients of grayscale values in each image. The final step involves a simplification of the model that is achieved by eliminating the terms that couple the membrane potentials of adjacent neurons. We apply our technique to detect edges in data sets of artificially generated and real images, and we demonstrate that the performance is as good if not better than that of the previous methods without increasing the size of the network.

  4. The relaxation time of processes in a FitzHugh-Nagumo neural system with time delay

    Energy Technology Data Exchange (ETDEWEB)

    Gong Ailing; Zeng Chunhua [Faculty of Science, Kunming University of Science and Technology, Kunming 650093 (China); Wang Hua, E-mail: zchh2009@126.com [Province Engineering Research Center of Industrial Energy Conservation and New Technology, Kunming University of Science and Technology, Kunming, Yunnan 650093 (China)

    2011-08-01

    In this paper, we study the relaxation time (RT) of the steady-state correlation function in a FitzHugh-Nagumo neural system under the presence of multiplicative and additive white noises and time delay. The noise correlation parameter {lambda} can produce a critical behavior in the RT as functions of the multiplicative noise intensity D, the additive noise intensity Q and the time delay {tau}. That is, the RT decreases as the noise intensities D and Q increase, and increases as the time delay {tau} increases below the critical value of {lambda}. However, above the critical value, the RT first increases, reaches a maximum, and then decreases as D, Q and {tau} increase, i.e. a noise intensity D or Q and a time delay {tau} exist, at which the time scales of the relaxation process are at their largest. In addition, the additive noise intensity Q can also produce a critical behavior in the RT as a function of {lambda}. The noise correlation parameter {lambda} first increases the RT of processes, then decreases it below the critical value of Q. Above the critical value, {lambda} increases it.

  5. Robust Synchronization of Delayed Chaotic FitzHugh-Nagumo Neurons under External Electrical Stimulation

    Directory of Open Access Journals (Sweden)

    Muhammad Rehan

    2012-01-01

    Full Text Available Synchronization of chaotic neurons under external electrical stimulation (EES is studied in order to understand information processing in the brain and to improve the methodologies employed in the treatment of cognitive diseases. This paper investigates the dynamics of uncertain coupled chaotic delayed FitzHugh-Nagumo (FHN neurons under EES for incorporated parametric variations. A global nonlinear control law for synchronization of delayed neurons with known parameters is developed. Based on local and global Lipschitz conditions, knowledge of the bounds on the neuronal states, the Lyapunov-Krasovskii functional, and the L2 gain reduction, a less conservative local robust nonlinear control law is formulated to address the problem of robust asymptotic synchronization of delayed FHN neurons under parametric uncertainties. The proposed local control law guarantees both robust stability and robust performance and provides the L2 bound for uncertainty rejection in the synchronization error dynamics. Separate conditions for single-input and multiple-input control schemes for synchronization of a wide class of FHN systems are provided. The results of the proposed techniques are verified through numerical simulations.

  6. THE ONE-DIMENSIONAL HUGHES MODEL FOR PEDESTRIAN FLOW: RIEMANN-TYPE SOLUTIONS

    Institute of Scientific and Technical Information of China (English)

    Debora Amadori; M. Di Francesco

    2012-01-01

    This paper deals with a coupled system consisting of a scalar conservation law and an eikonal equation,called the Hughes model.Introduced in [24],this model attempts to describe the motion of pedestrians in a densely crowded region,in which they are seen as a 'thinking' (continuum) fluid.The main mathematical difficulty is the discontinuous gradient of the solution to the eikonal equation appearing in the flux of the conservation law.On a one dimensional interval with zero Dirichlet conditions (the two edges of the interval are interpreted as 'targets'),the model can be decoupled in a way to consider two classical conservation laws on two sub-domains separated by a turning point at which the pedestrians change their direction.We shall consider solutions with a possible jump discontinuity around the turning point.For simplicity,we shall assume they are locally constant on both sides of the discontinuity.We provide a detailed description of the localin-time behavior of the solution in terms of a 'global' qualitative property of the pedestrian density (that we call 'relative evacuation rate'),which can be interpreted as the attitude of the pedestrians to direct towards the left or the right target.We complement our result with explicitly computable examples.

  7. Noise-sustained synchronization between electrically coupled FitzHugh-Nagumo networks

    Science.gov (United States)

    Cascallares, Guadalupe; Sánchez, Alejandro D.; dell'Erba, Matías G.; Izús, Gonzalo G.

    2015-09-01

    We investigate the capability of electrical synapses to transmit the noise-sustained network activity from one network to another. The particular setup we consider is two identical rings with excitable FitzHugh-Nagumo cell dynamics and nearest-neighbor antiphase intra-ring coupling, electrically coupled between corresponding nodes. The whole system is submitted to independent local additive Gaussian white noises with common intensity η, but only one ring is externally forced by a global adiabatic subthreshold harmonic signal. We then seek conditions for a particular noise level to promote synchronized stable firing patterns. By running numerical integrations with increasing η, we observe the excitation activity to become spatiotemporally self-organized, until η is so strong that spoils sync between networks for a given value of the electric coupling strength. By means of a four-cell model and calculating the stationary probability distribution, we obtain a (signal-dependent) non-equilibrium potential landscape which explains qualitatively the observed regimes, and whose barrier heights give a good estimate of the optimal noise intensity for the sync between networks.

  8. Subthreshold and suprathreshold vibrational resonance in the FitzHugh-Nagumo neuron model

    Science.gov (United States)

    Zhu, Jinjie; Kong, Chen; Liu, Xianbin

    2016-09-01

    We study the subthreshold and suprathreshold vibrational resonance in the FitzHugh-Nagumo neuron model. For the subthreshold situation, two cases where the stationary states are equilibrium point and limit cycle are considered, where different natures of vibrational resonance are observed via theoretical and numerical methods. Especially when the frequency of the high-frequency driving force is near the so-called canard-resonance frequency, the firing rate can be significantly enhanced at the presence of noise. For the suprathreshold situation, we show that the local maxima of the response amplitude are located at the transition boundaries of different phase-locking patterns. The minimal required forcing amplitudes of high-frequency signal of the firing onset are just multiples of the spiking frequency. Furthermore, phase portraits and time series show that the presence of the global maxima of the response results from not only the suprathreshold but also the subthreshold phase-locking modes. In spite of the distinct characteristics for two stationary states on subthreshold oscillation, the suprathreshold vibrational resonance showed no qualitative difference between the two cases.

  9. Adaptable Analytical Vistas Illumine a Touchstone: Langston Hughes as Minor Author/Poet

    Directory of Open Access Journals (Sweden)

    Mzenga A. Wanyama

    2013-12-01

    Full Text Available The authentic association of spontaneity, as a spur or basis for artistic expression, with the vaunted notion of autonomy in literary creationis nowhere more clearly established than in the work of theorists Gilles Deleuze and Felix Guattari as they, inter-alia, explicate the unique literary repertoire bestowed upon the world by Franz Kafka. In their acclaimed works: Kafka: Toward a Minor Literature and Anti-Oedipus: Capitalism and Schizophrenia,they offered to literary theory the fascinating and analytically productive constructs of deterritorialization and anti-Oedipus in the context of a compelling portraiture of the ways in which various institutionalized relationships subtly prescribe and reinforce inequity in society’s power mechanics that tendentiously impact, among other realities, the nature and quality of literary products. They offered, in the process, a refreshing definition of minor literature that unequivocally restores to literature its distinctive place and role in the amalgamated adjudications of society’s intergroup dissensions. In this regard, the present paper subscribes to the idea that spontaneity equaled the intrinsic and immutable desire of the gifted literary mind of African-American author/poet Langston Hughes to reach expressivity in accordance, strictly, with his unalloyed literary vision and thus made autonomy the inevitable upshot of his inspiration and practice.

  10. Optical Hall effect in strained graphene

    Science.gov (United States)

    Nguyen, V. Hung; Lherbier, A.; Charlier, J.-C.

    2017-06-01

    When passing an optical medium in the presence of a magnetic field, the polarization of light can be rotated either when reflected at the surface (Kerr effect) or when transmitted through the material (Faraday rotation). This phenomenon is a direct consequence of the optical Hall effect arising from the light-charge carrier interaction in solid state systems subjected to an external magnetic field, in analogy with the conventional Hall effect. The optical Hall effect has been explored in many thin films and also more recently in 2D layered materials. Here, an alternative approach based on strain engineering is proposed to achieve an optical Hall conductivity in graphene without magnetic field. Indeed, strain induces lattice symmetry breaking and hence can result in a finite optical Hall conductivity. First-principles calculations also predict this strain-induced optical Hall effect in other 2D materials. Combining with the possibility of tuning the light energy and polarization, the strain amplitude and direction, and the nature of the optical medium, large ranges of positive and negative optical Hall conductivities are predicted, thus opening the way to use these atomistic thin materials in novel specific opto-electro-mechanical devices.

  11. The quantum Hall effects: Philosophical approach

    Science.gov (United States)

    Lederer, P.

    2015-05-01

    The Quantum Hall Effects offer a rich variety of theoretical and experimental advances. They provide interesting insights on such topics as gauge invariance, strong interactions in Condensed Matter physics, emergence of new paradigms. This paper focuses on some related philosophical questions. Various brands of positivism or agnosticism are confronted with the physics of the Quantum Hall Effects. Hacking's views on Scientific Realism, Chalmers' on Non-Figurative Realism are discussed. It is argued that the difficulties with those versions of realism may be resolved within a dialectical materialist approach. The latter is argued to provide a rational approach to the phenomena, theory and ontology of the Quantum Hall Effects.

  12. Quantum Hall Effect in Higher Dimensions

    CERN Document Server

    Karabali, Dimitra; Karabali, Dimitra

    2002-01-01

    Following recent work on the quantum Hall effect on $S^4$, we solve the Landau problem on the complex projective spaces ${\\bf C}P^k$ and discuss quantum Hall states for such spaces. Unlike the case of $S^4$, a finite spatial density can be obtained with a finite number of internal states for each particle. We treat the case of ${\\bf C}P^2$ in some detail considering both Abelian and nonabelian background fields. The wavefunctions are obtained and incompressibility of the Hall states is shown. The case of ${\\bf C}P^3$ is related to the case of $S^4$.

  13. Joule heating in spin Hall geometry

    Science.gov (United States)

    Taniguchi, Tomohiro

    2016-07-01

    The theoretical formula for the entropy production rate in the presence of spin current is derived using the spin-dependent transport equation and thermodynamics. This theory is applicable regardless of the source of the spin current, for example, an electric field, a temperature gradient, or the Hall effect. It reproduces the result in a previous work on the dissipation formula when the relaxation time approximation is applied to the spin relaxation rate. By using the developed theory, it is found that the dissipation in the spin Hall geometry has a contribution proportional to the square of the spin Hall angle.

  14. Piezo Voltage Controlled Planar Hall Effect Devices

    Science.gov (United States)

    Zhang, Bao; Meng, Kang-Kang; Yang, Mei-Yin; Edmonds, K. W.; Zhang, Hao; Cai, Kai-Ming; Sheng, Yu; Zhang, Nan; Ji, Yang; Zhao, Jian-Hua; Zheng, Hou-Zhi; Wang, Kai-You

    2016-06-01

    The electrical control of the magnetization switching in ferromagnets is highly desired for future spintronic applications. Here we report on hybrid piezoelectric (PZT)/ferromagnetic (Co2FeAl) devices in which the planar Hall voltage in the ferromagnetic layer is tuned solely by piezo voltages. The change of planar Hall voltage is associated with magnetization switching through 90° in the plane under piezo voltages. Room temperature magnetic NOT and NOR gates are demonstrated based on the piezo voltage controlled Co2FeAl planar Hall effect devices without the external magnetic field. Our demonstration may lead to the realization of both information storage and processing using ferromagnetic materials.

  15. Piezo Voltage Controlled Planar Hall Effect Devices.

    Science.gov (United States)

    Zhang, Bao; Meng, Kang-Kang; Yang, Mei-Yin; Edmonds, K W; Zhang, Hao; Cai, Kai-Ming; Sheng, Yu; Zhang, Nan; Ji, Yang; Zhao, Jian-Hua; Zheng, Hou-Zhi; Wang, Kai-You

    2016-06-22

    The electrical control of the magnetization switching in ferromagnets is highly desired for future spintronic applications. Here we report on hybrid piezoelectric (PZT)/ferromagnetic (Co2FeAl) devices in which the planar Hall voltage in the ferromagnetic layer is tuned solely by piezo voltages. The change of planar Hall voltage is associated with magnetization switching through 90° in the plane under piezo voltages. Room temperature magnetic NOT and NOR gates are demonstrated based on the piezo voltage controlled Co2FeAl planar Hall effect devices without the external magnetic field. Our demonstration may lead to the realization of both information storage and processing using ferromagnetic materials.

  16. The fluctuation Hall conductivity and the Hall angle in type-II superconductor under magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Tinh, Bui Duc, E-mail: tinhbd@hnue.edu.vn [Institute of Research and Development, Duy Tan University, K7/25 Quang Trung, Danang (Viet Nam); Department of Physics, Hanoi National University of Education, 136 Xuan Thuy, Cau Giay, Hanoi (Viet Nam); Hoc, Nguyen Quang; Thu, Le Minh [Department of Physics, Hanoi National University of Education, 136 Xuan Thuy, Cau Giay, Hanoi (Viet Nam)

    2016-02-15

    Highlights: • The time-dependent Ginzburg–Landau was used to calculate fluctuation Hall conductivity and Hall angle in type-II superconductor in 2D and 3D. • We obtain analytical expressions for the fluctuation Hall conductivity and the Hall angle summing all Landau levels without need to cutoff higher Landau levels to treat arbitrary magnetic field. • The results were compared to the experimental data on YBCO. - Abstract: The fluctuation Hall conductivity and the Hall angle, describing the Hall effect, are calculated for arbitrary value of the imaginary part of the relaxation time in the frame of the time-dependent Ginzburg–Landau theory in type II-superconductor with thermal noise describing strong thermal fluctuations. The self-consistent Gaussian approximation is used to treat the nonlinear interaction term in dynamics. We obtain analytical expressions for the fluctuation Hall conductivity and the Hall angle summing all Landau levels without need to cutoff higher Landau levels to treat arbitrary magnetic field. The results are compared with experimental data on high-T{sub c} superconductor.

  17. Light Metal Propellant Hall Thruster Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Busek proposes to develop light metal Hall Effect thrusters that will help reduce the travel time, mass, and cost of SMD spacecraft. Busek has identified three...

  18. Success of Hall technique crowns questioned.

    Science.gov (United States)

    Nainar, S M Hashim

    2012-01-01

    Hall technique is a method of providing stainless steel crowns for primary molars without tooth preparation and requires no local anesthesia. Literature review showed inconclusive evidence and therefore this technique should not be used in clinical practice.

  19. Dual Mode Low Power Hall Thruster Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Sample and return missions desire and missions like Saturn Observer require a low power Hall thruster that can operate at high thrust to power as well as high...

  20. Iodine Hall Thruster for Space Exploration Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Busek Co. Inc. proposes to develop a high power (high thrust) electric propulsion system featuring an iodine fueled Hall Effect Thruster (HET). The system to be...

  1. The phonon Hall effect: theory and application

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Lifa; Wang Jiansheng; Li Baowen [Department of Physics and Centre for Computational Science and Engineering, National University of Singapore, Singapore 117542 (Singapore); Ren Jie [NUS Graduate School for Integrative Sciences and Engineering, Singapore 117456 (Singapore)

    2011-08-03

    We present a systematic theory of the phonon Hall effect in a ballistic crystal lattice system, and apply it on the kagome lattice which is ubiquitous in various real materials. By proposing a proper second quantization for the non-Hermitian in the polarization-vector space, we obtain a new heat current density operator with two separate contributions: the normal velocity responsible for the longitudinal phonon transport, and the anomalous velocity manifesting itself as the Hall effect of transverse phonon transport. As exemplified in kagome lattices, our theory predicts that the direction of Hall conductivity at low magnetic field can be reversed by tuning the temperatures, which we hope can be verified by experiments in the future. Three phonon-Hall-conductivity singularities induced by phonon-band-topology change are discovered as well, which correspond to the degeneracies at three different symmetric center points, {Gamma}, K, X, in the wavevector space of the kagome lattice.

  2. Students halls – humane lifestyle for students

    Directory of Open Access Journals (Sweden)

    Igor Seljak

    2000-01-01

    Full Text Available With the increasing number of students at the University of Ljubljana (Slovenia, the shortage of student’s accommodation in student’s halls has increased. Alongside the necessity for building new accommodation capacities an opportunity has emerged for the enforcement of new living standards that should replace outdated guidelines from the sixties. During the preparation of the project we analysed all the important elements of students accommodation in students halls. Analyses of the present conditions in existing halls were performed, including positive and negative elements. We also conducted a comparative research of student’s halls in various European countries. In conclusion a list of recommendations with real guidelines was prepared that could be used by investors when proposing new development of such buildings, as well as architects and planners.

  3. Athletics hall, Odenwald school, Heppenheim, Germany

    Energy Technology Data Exchange (ETDEWEB)

    Schuler, M. [Trans Solar GmbH, Stuttgart (Germany)

    1999-07-01

    This building, completed in 1995, is a good example of how to use a glazed foyer, not only as a climatic buffer zone, but also for preheating the inlet air by solar gains. The completely glazed west-oriented foyer is used as a huge air collector to preheat ventilation air during the heating period. The glass superstructure across the hall stores a movable curtain, serves as a skylight and enhances the natural ventilation of the hall due to the chimney effect. The stiffening ribs of the floor are also used as an air duct to the hall and as an installation duct. Photovoltaic-powered fans are used to move solar preheated air into the hall. (author)

  4. Quantum Hall effect in momentum space

    Science.gov (United States)

    Ozawa, Tomoki; Price, Hannah M.; Carusotto, Iacopo

    2016-05-01

    We theoretically discuss a momentum-space analog of the quantum Hall effect, which could be observed in topologically nontrivial lattice models subject to an external harmonic trapping potential. In our proposal, the Niu-Thouless-Wu formulation of the quantum Hall effect on a torus is realized in the toroidally shaped Brillouin zone. In this analogy, the position of the trap center in real space controls the magnetic fluxes that are inserted through the holes of the torus in momentum space. We illustrate the momentum-space quantum Hall effect with the noninteracting trapped Harper-Hofstadter model, for which we numerically demonstrate how this effect manifests itself in experimental observables. Extension to the interacting trapped Harper-Hofstadter model is also briefly considered. We finally discuss possible experimental platforms where our proposal for the momentum-space quantum Hall effect could be realized.

  5. Multiscale Modeling of Hall Thrusters Project

    Data.gov (United States)

    National Aeronautics and Space Administration — New multiscale modeling capability for analyzing advanced Hall thrusters is proposed. This technology offers NASA the ability to reduce development effort of new...

  6. Observation of the magnon Hall effect.

    Science.gov (United States)

    Onose, Y; Ideue, T; Katsura, H; Shiomi, Y; Nagaosa, N; Tokura, Y

    2010-07-16

    The Hall effect usually occurs in conductors when the Lorentz force acts on a charge current in the presence of a perpendicular magnetic field. Neutral quasi-particles such as phonons and spins can, however, carry heat current and potentially exhibit the thermal Hall effect without resorting to the Lorentz force. We report experimental evidence for the anomalous thermal Hall effect caused by spin excitations (magnons) in an insulating ferromagnet with a pyrochlore lattice structure. Our theoretical analysis indicates that the propagation of the spin waves is influenced by the Dzyaloshinskii-Moriya spin-orbit interaction, which plays the role of the vector potential, much as in the intrinsic anomalous Hall effect in metallic ferromagnets.

  7. Hall effect degradation of rail gun performance

    Science.gov (United States)

    Witalis, E. A.; Gunnarsson, Patrik

    1993-01-01

    The paper discusses the Hall effect and shows it to be significant in the low-density and high-field trailing part of a plasma armature. Without the Hall effect a simple armature model is derived. It exhibits properties expected from classical MHD theory and shows that the purely relativistic electric charge buildup on the rails is a fundamental gun property, leading to V(breech) = 1.5 V(muzzle). The mathematics involved in accounting for Hall effect phenomena is described. These are of two types: the Hall-skewing of the armature current and the superimposed plasma flow rotation. For decreasing gun current the two effects efficiently combine to eject armature plasma rearwards, thus creating conditions for arc separation and parasitic arcs.

  8. Iodine Hall Thruster for Space Exploration Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In the Phase I program, Busek Co. Inc. tested an existing Hall thruster, the BHT-8000, on iodine propellant. The thruster was fed by a high flow iodine feed system,...

  9. 75 FR 7467 - Gary E. Hall and Rita C. Hall; Notice of Application Accepted for Filing With the Commision...

    Science.gov (United States)

    2010-02-19

    .... Applicant: Gary E. Hall and Rita C. Hall. e. Name of Project: Potter Creek Hydroelectric Project. f. Location: The project is located on Potter Creek in Flathead County, Montana. The project would be located...: Mr. Gary E. Hall and Ms. Rita C. Hall, P.O. Box 133, Olney, MT 59927, (406) 881-2345. i. FERC Contact...

  10. OBITUARY: Eur.Ing. Professor David Dew-Hughes in memoriam

    Science.gov (United States)

    Campbell, Archie; Dew-Hughes, Denise; Donaldson, Gordon; Palmer, Richard

    2007-06-01

    We regret to announce the death of David Dew-Hughes, the second Honorary Editor of Superconductor Science and Technology, in Autumn 2006. He was born in Manchester, the eldest of three children, attended Manchester Grammar School and took his first degree in metallurgy at Birmingham, before undertaking a Doctorate of Engineering at Yale University. After initial work for IBM on semiconductors, he returned to England as a lecturer in metallurgy at Cambridge University. There he devoted his career to superconductivity long before it became fashionable, starting a group on the properties of what we now know as type II materials, with his students Jan Evetts, Archie Campbell and Anant Narlikar. Between them they paved the way to our understanding of the magnetic vortex properties of these materials, and thus to the development of modern practical materials for superconducting magnets. Eur.Ing. Professor David Dew-Hughes 1932-2006 In 1965 he became a founding Senior Lecturer in physics at Lancaster University, moving to Brookhaven National Laboratory in 1974. His final academic post was in engineering science at Oxford University where he also held a University College Tutorial Fellowship. As long ago as 1971 David wrote an authoritative review for Reports on Progress in Physics on 'The metallurgical enhancement of type II superconductors'. Following the discovery of high-Tc superconductivity, IOP Publishing launched Superconductor Science and Technology in 1988 and he was a founder member of its Editorial Board. When Jan Evetts retired as Honorary Editor in 1992, David was the natural choice as his successor. He served a five year term and remained on the Board as Deputy Editor until the end of 2000. To mark the 10th anniversary of high-temperature superconductivity in 1997, David edited a special issue of Superconductor Science and Technology in which past and present members of the Editorial Board contributed reviews of their specialities. He noted that at that time

  11. Cohomological Hall algebras and character varieties

    CERN Document Server

    Davison, Ben

    2015-01-01

    In this paper we investigate the relationship between twisted and untwisted character varieties via a specific instance of the Cohomological Hall algebra for moduli of objects in 3-Calabi-Yau categories introduced by Kontsevich and Soibelman. In terms of Donaldson--Thomas theory, this relationship is completely understood via the calculations of Hausel and Villegas of the E polynomials of twisted character varieties and untwisted character stacks. We present a conjectural lift of this relationship to the cohomological Hall algebra setting.

  12. Hall effect on the triangular lattice

    OpenAIRE

    Leon Suros, Gladys Eliana; Berthod, Christophe; Giamarchi, Thierry; Millis, A.

    2008-01-01

    We investigate the high frequency Hall effect on a two-dimensional triangular lattice with nearest-neighbor hopping and a local Hubbard interaction. The complete temperature and doping dependencies of the high-frequency Hall coefficient $R_H$ are evaluated analytically and numerically for small, intermediate, and strong interactions using various approximation schemes. We find that $R_H$ follows the semiclassical $1/qn^*$ law near T=0, but exhibits a striking $T$-linear behavior with an inter...

  13. Are tent halls subject to property tax?

    Directory of Open Access Journals (Sweden)

    Mariusz Macudziński

    2016-12-01

    Full Text Available The presented publication is a response to currently asked questions and interpretative doubts of taxpayers and tax authorities, namely whether tent halls are subject to property tax. General issues connected with an entity and a subject of taxation of this tax are presented herein. The answer to the question asked is then provided through the qualification of constructions works and the allocation of tent halls in the proper category of the works, with the use of the current law.

  14. Piezo Voltage Controlled Planar Hall Effect Devices

    OpenAIRE

    Bao Zhang; Kang-Kang Meng; Mei-Yin Yang; Edmonds, K. W.; Hao Zhang; Kai-Ming Cai; Yu Sheng; Nan Zhang; Yang Ji; Jian-Hua Zhao; Hou-Zhi Zheng; Kai-You Wang

    2015-01-01

    The electrical control of the magnetization switching in ferromagnets is highly desired for future spintronic applications. Here we report on hybrid piezoelectric (PZT)/ferromagnetic (Co2FeAl) devices in which the planar Hall voltage in the ferromagnetic layer is tuned solely by piezo voltages. The change of planar Hall voltage is associated with magnetization switching through 90° in the plane under piezo voltages. Room temperature magnetic NOT and NOR gates are demonstrated based on the pie...

  15. Hall effect in organic layered conductors

    Directory of Open Access Journals (Sweden)

    R.A.Hasan

    2006-01-01

    Full Text Available The Hall effect in organic layered conductors with a multisheeted Fermi surfaces was considered. It is shown that the experimental study of Hall effect and magnetoresistance anisotropy at different orientations of current and a quantizing magnetic field relative to the layers makes it possible to determine the contribution of various charge carriers groups to the conductivity, and to find out the character of Fermi surface anisotropy in the plane of layers.

  16. An introduction to motivic Hall algebras

    CERN Document Server

    Bridgeland, Tom

    2010-01-01

    We give an introduction to Joyce's construction of the motivic Hall algebra of coherent sheaves on a variety M. When M is a Calabi-Yau threefold we define a semi-classical integration map from a Poisson subalgebra of this Hall algebra to the ring of functions on a symplectic torus. This material will be used in arxiv:1002.4374 to prove some basic properties of Donaldson-Thomas curve-counting invariants on Calabi-Yau threefolds.

  17. CT Diagnosis of Fitz-Hugh and Curtis Syndrome: Value of the Arterial Phase Scan

    Energy Technology Data Exchange (ETDEWEB)

    Joo, Seung Ho; Kim, Myeong Jin; Lim, Joon Seok; Kim, Joo Hee; Kim, Ki Whang [Yonsei University College of Medicine, Seoul (Korea, Republic of)

    2007-02-15

    We wanted to evaluate the role of the arterial phase (AP) together with the portal venous phase (PP) scans in the diagnosis of Fitz-Hugh-Curtis syndrome (FHCS) with using computed tomography (CT). Twenty-five patients with FHCS and 25 women presenting with non-specifically diagnosed acute abdominal pain and who underwent biphasic CT examinations were evaluated. The AP scan included the upper abdomen, and the PP scan included the whole abdomen. Two radiologists blindly and retrospectively reviewed the PP scans first and then they reviewed the AP plus PP scans. The diagnostic accuracy of FHCS on each image set was compared for each reader by analyzing the area under the receiver operating characteristic curve (Az). Weighted kappa (wk) statistics were used to measure the interobserver agreement for the presence of CT signs of the pelvic inflammatory disease (PID) on the PP images and FHCS as the diagnosis based on the increased perihepatic enhancement on both sets of images. The individual diagnostic accuracy of FHCS was higher on the biphasic images (Az = 0.905 and 0.942 for reader 1 and 2, respectively) than on the PP images alone (Az = 0.806 and 0.706, respectively). The interobserver agreement for the presence of PID on the PP images was moderate (wk = 0.530). The interobserver agreement for FHCS as the diagnosis was moderate on only the PP images (wk = 0.413), but it was substantial on the biphasic images (wk 0.719). Inclusion of the AP scan is helpful to depict the increased perihepatic enhancement, and it improves the diagnostic accuracy of FHCS on CT.

  18. Turbulence Measurements in a Tropical Zoo Hall

    Science.gov (United States)

    Eugster, Werner; Denzler, Basil; Bogdal, Christian

    2017-04-01

    The Masoala rainforest hall of the Zurich Zoo, Switzerland, covers a ground surface area of 10,856 m2 and reaches 30 m in height. With its transparent ETFE foiled roof it provides a tropical climate for a large diversity of plants and animals. In combination with an effort to estimate dry deposition of elemental mercury, we made an attempt to measure turbulent transfer velocity with an ultrasonic anemometer inside the hall. Not surprising, the largest turbulence elements were on the order of the hall dimension. Although the dimensions of the hall seem to be small (200,000 m3) for eddy covariance flux measurements and the air circulation inside the hall was extremely weak, the spectra of wind velocity components and virtual (sonic) temperature obeyed the general statistical description expected under unconstrained outdoor measurement conditions. We will present results from a two-week measurement campaign in the Masoala rainforest hall and make a suggestion for the deposition velocity to be used to estimate dry deposition of atmospheric components to the tropical vegetation surface.

  19. 75 FR 22770 - Gary E. Hall and Rita Hall; Notice of Availability of Environmental Assessment

    Science.gov (United States)

    2010-04-30

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Gary E. Hall and Rita Hall; Notice of Availability of Environmental Assessment April 22, 2010. In accordance with the National Environmental Policy Act of 1969, as amended,...

  20. How Hugh Hampton Young's treatment of President Woodrow Wilson's urinary retention and urosepsis affected the resolution of World War I.

    Science.gov (United States)

    Fogg, Ryan; Kutikov, Alexander; Uzzo, Robert G; Canter, Daniel

    2011-09-01

    President Woodrow Wilson was never able to gain ratification of the Treaty of Versailles, the peace accord to end World War I. Before he could convince the American people of the importance of ratification, Wilson suffered a stroke followed by life threatening urinary sepsis due to urinary retention, and was treated by the father of modern urology, Hugh Hampton Young. The effects of these health problems are examined in the context of their implications on international affairs. Biographical sources and primary documentation of Wilson's physicians were reviewed to determine the effect of Wilson's stroke on his voiding habits. Hugh Hampton Young's evaluation and decision making is examined in depth. In the fall of 1919 President Wilson was recovering from a stroke. Shortly after the stroke his preexisting voiding dysfunction progressed to urinary retention from which urinary sepsis developed. Hugh Hampton Young advised on Wilson's case and counseled patience over surgery. The President began voiding spontaneously and recovered from sepsis. The illness left him severely weakened and unable to mount an aggressive campaign to persuade the U.S. Senate of the importance of ratifying the Treaty of Versailles. His personal physician, Admiral Cary T. Grayson, stated that the President was mentally never the same after the sepsis. Wilson's voiding dysfunction contributed to his inability to win approval for the Treaty of Versailles and the League of Nations. As a result, the United States returned to a policy of isolationism and Europe plunged into 2 decades of upheaval, leading to World War II. Copyright © 2011 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

  1. Charge carrier coherence and Hall effect in organic semiconductors.

    Science.gov (United States)

    Yi, H T; Gartstein, Y N; Podzorov, V

    2016-03-30

    Hall effect measurements are important for elucidating the fundamental charge transport mechanisms and intrinsic mobility in organic semiconductors. However, Hall effect studies frequently reveal an unconventional behavior that cannot be readily explained with the simple band-semiconductor Hall effect model. Here, we develop an analytical model of Hall effect in organic field-effect transistors in a regime of coexisting band and hopping carriers. The model, which is supported by the experiments, is based on a partial Hall voltage compensation effect, occurring because hopping carriers respond to the transverse Hall electric field and drift in the direction opposite to the Lorentz force acting on band carriers. We show that this can lead in particular to an underdeveloped Hall effect observed in organic semiconductors with substantial off-diagonal thermal disorder. Our model captures the main features of Hall effect in a variety of organic semiconductors and provides an analytical description of Hall mobility, carrier density and carrier coherence factor.

  2. The ingenious Mr Hughes: Combining forced, flat, and reverse perspective all in one art piece to pit objects against surfaces

    Science.gov (United States)

    Papathomas, Thomas V; Baker, Nicholas; Yeshua, Arielle S; Zhuang, Xiaohua; Ng, Andrew

    2012-01-01

    The artist Patrick Hughes has ingeniously painted rows of stacked Brillo boxes in Forced into Reverse Perspective. The geometry is in reverse perspective, predicting only one type of illusory motion for each planar surface for moving viewers. He “broke” these surfaces into objects by painting the boxes in three types of perspective (planar, forced, and reverse). Our experiments confirmed that he succeeded in eliciting different types of illusory motion, including “differential motion” between boxes for most viewers. In some sense, this illustrates the superiority of secondary (painted) over primary (physical) cues. PMID:23145280

  3. The Ingenious Mr Hughes: Combining Forced, Fat, and Reverse Perspective All in One Art Piece to Pit Objects against Surfaces

    Directory of Open Access Journals (Sweden)

    Thomas V Papathomas

    2012-04-01

    Full Text Available The artist Patrick Hughes has ingeniously painted rows of stacked Brillo boxes in Forced into Reverse Perspective. The geometry is in reverse perspective, predicting only one type of illusory motion for each planar surface for moving viewers. He “broke” these surfaces into objects by painting the boxes in three types of perspective (planar, forced, and reverse. Our experiments confirmed that he succeeded in eliciting different types of illusory motion, including “differential motion” between boxes for most viewers. In some sense, this illustrates the superiority of secondary (painted over primary (physical cues.

  4. Maurice Hugh Frederick Wilkins CBE: 15 December 1916 - 5 October 2004.

    Science.gov (United States)

    Arnott, Struther; Kibble, T W B; Shallice, Tim

    2006-01-01

    Maurice Hugh Frederick Wilkins was the 'Third man of the double helix; according to the publishers who were allowed to foist this title on his late-written autobiography. Certainly it is for his role in the discover of the duplex secondary structure of DNA that he will be remembered. It might be argued that he was the first man, rather than the third, for it was his successful revival of X-ray diffraction studies of DNA and his earliest result in 1950, a pattern of a well-oriented and polycrystalline DNA of unprecedented quality, that allowed him to conclude almost immediately that the basic framework of the genetical material was simple and symmetrical, and that the symmetrical structure took the form of a helix. This same pattern, displayed at a conference in Naples six months later, was the major inspiration for the involvement of J. D. Watson (ForMemRS 1981) in modelling DNA structure in collaboration with F. H. C. Crick (FRS 1959). Crick was a personal friend of Maurice's and was more involved with studies of proteins until the progress of Maurice's research programme and Watson's enthusiastic presence in Cambridge convinced him to put nucleic acids first. The carefully crafted citation for the 1960 Lasker Award, which these three men shared in 1960, put Maurice's name first and accurately referred to '...the painstaking x-ray diffraction studies of Wilkins that provided a most important clue that was pursued in a ingenious fashion and to a logical conclusion by Crick and Watson...'. Maurice's diffraction studies of DNA were not only the alpha but also the omega of the double helix because it left to him to remedy a major flaw in the original (1953) Watson-Crick conjecture. Maurice Wilkin's early acceptance of DNA as the genetic material and his recognition that it had structures that could and should be tackled by X-ray diffraction analyses, not necessarily under his exclusive control, was important in ensuring that the essence of DNA's structure was

  5. PROFESSOR ALEX I. MENKITI

    African Journals Online (AJOL)

    90 dB (A) LAeq.with exchange rate of 3 dB (A) ... gas exploration are all areas where acoustics .... The model assumed for a freely flowing traffic is that of ..... Table 1b: Static deflection and natural frequency of some vibration and ...... (3 -~> water fiawiru; into \\'lt'£f taxxit; MAWMWMWM ...... Heat and Noise Problems in a Drug.

  6. Edge reconstructions in fractional quantum Hall systems.

    Science.gov (United States)

    Joglekar, Yogesh; Nguyen, Hoang; Murthy, Ganpathy

    2003-03-01

    Two dimensional electron systems exhibiting fractional quantum Hall effects are characterized by a quantized Hall conductance and a dissipationless bulk. The transport in these systems occurs only at the edges where gapless excitations are possible [1]. We present a microscopic calculation of these egde-states at filling factors ν=1/3 and ν=2/5 using the Hamiltonian theory of the fractional quantum Hall effect [2]. We find that the quantum Hall egde undergoes a reconstruction as the confining potential, produced by the background charge density, softens [3,4]. Our results have implications to the tunneling experiments into the edge of a fractional quantum Hall system [5]. 1: X. G.Wen, Phys. Rev. Lett. 64, 2206 (1990). 2: R. Shankar and G. Murthy, Phys. Rev. Lett. 79, 4437 (1997). 3: C. de C. Chamon and X. G. Wen, Phys. Rev. B 49, 8227 (1994). 4: X. Wan, K. Yang, and E. H. Razayi, Phys. Rev. Lett. 88, 056802 (2002). 5: A.M.Chang et al., Phys. Rev. Lett. 86, 143 (2000).

  7. The Hall effect in star formation

    CERN Document Server

    Braiding, Catherine R

    2011-01-01

    Magnetic fields play an important role in star formation by regulating the removal of angular momentum from collapsing molecular cloud cores. Hall diffusion is known to be important to the magnetic field behaviour at many of the intermediate densities and field strengths encountered during the gravitational collapse of molecular cloud cores into protostars, and yet its role in the star formation process is not well-studied. We present a semianalytic self-similar model of the collapse of rotating isothermal molecular cloud cores with both Hall and ambipolar diffusion, and similarity solutions that demonstrate the profound influence of the Hall effect on the dynamics of collapse. The solutions show that the size and sign of the Hall parameter can change the size of the protostellar disc by up to an order of magnitude and the protostellar accretion rate by fifty per cent when the ratio of the Hall to ambipolar diffusivities is varied between -0.5 <= eta_H / eta_A <= 0.2. These changes depend upon the orien...

  8. Mobile Technologies in the Service of Students' Learning of Mathematics: The Example of Game Application A.L.E.X. in the Context of a Primary School in Cyprus

    Science.gov (United States)

    Kyriakides, Andreas O.; Meletiou-Mavrotheris, Maria; Prodromou, Theodosia

    2016-01-01

    This article reports on the main experiences gained from a 2-year study which incorporated A.L.E.X., an educational puzzle game available on iPad or Android tablet devices, within the primary school mathematics curriculum. The study took place in a public primary school, located in a rural area of Cyprus. The majority of its students come from low…

  9. Mode stability analysis in the beam-wave interaction process for a three-gap Hughes-type coupled cavity chain

    Institute of Scientific and Technical Information of China (English)

    Luo Ji-Run; Cui Jian; Zhu Min; Guo Wei

    2013-01-01

    Based on space-charge wave theory,the formulae of the beam-wave coupling coefficient and the beam-loaded conductance are given for the beam-wave interaction in an N-gap Hughes-type coupled cavity chain.The ratio of the nonbeam-loaded quality factor of the coupled cavity chain to the beam quality factor is used to determine the stability of the beam-wave interaction.As an example,the stabilities of the beam-wave interaction in a three-gap Hughes-type coupled cavity chain are discussed with the formulae and the CST code for the operations of the 2π,π,and π/2 modes,respectively.The results show that stable operation of the 2π,π,and π/2 modes may all be realized in an extended-interaction klystron with the three-gap Hughes-type coupled cavity chain.

  10. Mesoscopic effects in the quantum Hall regime

    Indian Academy of Sciences (India)

    R N Bhatt; Xin Wan

    2002-02-01

    We report results of a study of (integer) quantum Hall transitions in a single or multiple Landau levels for non-interacting electrons in disordered two-dimensional systems, obtained by projecting a tight-binding Hamiltonian to the corresponding magnetic subbands. In finite-size systems, we find that mesoscopic effects often dominate, leading to apparent non-universal scaling behavior in higher Landau levels. This is because localization length, which grows exponentially with Landau level index, exceeds the system sizes amenable to the numerical study at present. When band mixing between multiple Landau levels is present, mesoscopic effects cause a crossover from a sequence of quantum Hall transitions for weak disorder to classical behavior for strong disorder. This behavior may be of relevance to experimentally observed transitions between quantum Hall states and the insulating phase at low magnetic fields.

  11. Quantized photonic spin Hall effect in graphene

    Science.gov (United States)

    Cai, Liang; Liu, Mengxia; Chen, Shizhen; Liu, Yachao; Shu, Weixing; Luo, Hailu; Wen, Shuangchun

    2017-01-01

    We examine the photonic spin Hall effect (SHE) in a graphene-substrate system with the presence of an external magnetic field. In the quantum Hall regime, we demonstrate that the in-plane and transverse spin-dependent splittings in the photonic SHE exhibit different quantized behaviors. The quantized SHE can be described as a consequence of a quantized geometric phase (Berry phase), which corresponds to the quantized spin-orbit interaction. Furthermore, an experimental scheme based on quantum weak value amplification is proposed to detect the quantized SHE in the terahertz frequency regime. By incorporating the quantum weak measurement techniques, the quantized photonic SHE holds great promise for detecting quantized Hall conductivity and the Berry phase. These results may bridge the gap between the electronic SHE and photonic SHE in graphene.

  12. Graphene-based Hall Sensors for direct magnetic imaging by using Scanning Hall Probe Microscope

    Science.gov (United States)

    Sonusen, Selda; Aksoy, Seda; Dede, Munir; Oral, Ahmet

    2013-03-01

    Graphene has been attracting great interest due to its unique electronic and mechanical properties for both fundamental and experimental studies since 2004. Graphene is a promising material for many applications in high speed electronic and spintronic devices as well as sensors. Its high mobility makes graphene a good candidate for magnetic imaging in Scanning Hall Probe Microscope (SHPM). Hall probes are used to scan the magnetic samples to image magnetic domains in SHPM. In this work, single layer graphene produced by chemical vapor deposition technique is used to fabricate Hall sensors by optical and the e-beam lithography with sizes from 500 nm to a few micrometers. The Hall crosses are characterized by Raman mapping to make sure that they are made of a single layer graphene. The Graphene Hall Sensors noise spectra is measured as a function of different bias currents and carrier concentrations at 300 K, 77 K and 4.24K. The imaging performance of the Hall sensor will be demonstrated at different temperatures by imaging a garnet crystal using a Low Temperature Scanning Hall Probe Microscope (LT-SHPM).

  13. EL CROWN HALL. CONTEXTO Y PROYECTO

    Directory of Open Access Journals (Sweden)

    Laura Lizondo Sevilla

    2010-05-01

    Full Text Available RESUMEN El artículo enmarca el edificio del Crown Hall en el contexto docente y arquitectónico de Mies van der Rohe. Revisa sus inicios en la Bauhaus con su primera intervención en un espacio docente para la Bauhaus de Berlín en 1932, así como su marcha a Estados Unidos, los planteamientos arquitectónicos del campus del IIT y el proyecto del Crown Hall. El texto incide en el estudio del proceso proyectual del Crown Hall analizando la evolución de su concepción arquitectónica a través de las diferentes versiones del proyecto. Se constata la transición desde los primeros planteamientos arquitectónicos de los edificios del campus del IIT proyectados por Mies hacia el planteamiento del gran espacio unitario del Crown Hall. Este proyecto se puede entender desde la creciente importancia de la estructura, la claridad constructiva y el manejo del acero y vidrio como únicos materiales de la imagen del edificio y el carácter flexible y unitario del espacio. Finalmente se hace referencia al concepto del "espacio universal" en la arquitectura de Mies, como un concepto abstracto que supera los de flexibilidad de uso o unidad espacial, insinuando, a modo de reflexión, las principales variables que definirían el espacio universal miesiano.SUMMARY The article showcases the Crown Hall building in the educational and architectural context of Mies van der Rohe. It reviews his beginnings in the Bauhaus with his first intervention in an educational space for the Bauhaus of Berlin in 1932, as well as his sojourn to the United States, and the architectural approaches to the IIT campus and the Crown Hall project. The text touches on the study of the planning process for the Crown Hall, analysing the evolution of its architectural conception, through the different versions of the project. The article covers the transition from the first architectural approaches for the IIT campus buildings, planned by Mies, to the approach of the large unitary space of

  14. Acoustics in rock and pop music halls

    DEFF Research Database (Denmark)

    Adelman-Larsen, Niels Werner; Thompson, Eric Robert; Gade, Anders Christian

    2007-01-01

    The existing body of literature regarding the acoustic design of concert halls has focused almost exclusively on classical music, although there are many more performances of rhythmic music, including rock and pop. Objective measurements were made of the acoustics of twenty rock music venues...... in Denmark and a questionnaire was used in a subjective assessment of those venues with professional rock musicians and sound engineers. Correlations between the objective and subjective results lead, among others, to a recommendation for reverberation time as a function of hall volume. Since the bass...

  15. Inverse spin Hall effect by spin injection

    Science.gov (United States)

    Liu, S. Y.; Horing, Norman J. M.; Lei, X. L.

    2007-09-01

    Motivated by a recent experiment [S. O. Valenzuela and M. Tinkham, Nature (London) 442, 176 (2006)], the authors present a quantitative microscopic theory to investigate the inverse spin-Hall effect with spin injection into aluminum considering both intrinsic and extrinsic spin-orbit couplings using the orthogonalized-plane-wave method. Their theoretical results are in good agreement with the experimental data. It is also clear that the magnitude of the anomalous Hall resistivity is mainly due to contributions from extrinsic skew scattering.

  16. Integer quantum Hall effect in graphene

    Energy Technology Data Exchange (ETDEWEB)

    Jellal, Ahmed, E-mail: ahmed.jellal@gmail.com [Saudi Center for Theoretical Physics, Dhahran (Saudi Arabia); Theoretical Physics Group, Faculty of Sciences, Chouaïb Doukkali University, 24000 El Jadida (Morocco)

    2016-04-08

    We study the quantum Hall effect in a monolayer graphene by using an approach based on thermodynamical properties. This can be done by considering a system of Dirac particles in an electromagnetic field and taking into account of the edges effect as a pseudo-potential varying continuously along the x direction. At low temperature and in the weak electric field limit, we explicitly determine the thermodynamical potential. With this, we derive the particle numbers in terms of the quantized flux and therefore the Hall conductivity immediately follows.

  17. The portraiture of William Harvey (1578-1657) unveiled by the detective work of Geoffrey Keynes (1887-1983) and Alex Sakula (1917-2003).

    Science.gov (United States)

    James, D Geraint

    2005-05-01

    In November 1948, Sir Geoffrey Keynes exhibited the only known portrait of William Harvey in mid-life. The recovery of this rare portrait was due to Keynes's detective work at visits to Rolls Park in Essex. Dr Alex Sakula discovered the Betchworth portraits of the Harvey family by accident when he was invited to visit a patient, Major General Goulburn, at Betchworth in Surrey. After much research work Sakula was able to mount an informative exhibition at the Royal College of Physicians. Sakula also reminded us of Eliab Harvey (1758-1830), William's descendant, captain of the Téméraire at the Battle of Trafalgar; the year 2005 marks the bicentenary.

  18. Alex's Lemonade Stand Foundation Infant and Childhood Primary Brain and Central Nervous System Tumors Diagnosed in the United States in 2007-2011.

    Science.gov (United States)

    Ostrom, Quinn T; de Blank, Peter M; Kruchko, Carol; Petersen, Claire M; Liao, Peter; Finlay, Jonathan L; Stearns, Duncan S; Wolff, Johannes E; Wolinsky, Yingli; Letterio, John J; Barnholtz-Sloan, Jill S

    2015-01-01

    The CBTRUS Statistical Report: Alex's Lemonade Stand Foundation Infant and Childhood Primary Brain and Central Nervous System Tumors Diagnosed in the United States in 2007–2011 comprehensively describes the current population-based incidence of primary malignant and non-malignant brain and CNS tumors in children ages 0–14 years, collected and reported by central cancer registries covering approximately 99.8% of the United States population (for 2011 only, data were available for 50 out of 51 registries). Overall, brain and CNS tumors are the most common solid tumor, the most common cancer, and the most common cause of cancer death in infants and children 0–14 years. This report aims to serve as a useful resource for researchers, clinicians, patients, and families.

  19. The Great Detective, by Zach Dundas; Gender and the modern Sherlock Holmes, edited by Nadine Farghaly; and Sherlock Holmes, edited by Alex Werner [book review

    Directory of Open Access Journals (Sweden)

    Julia Knaus

    2017-03-01

    Full Text Available Review of: Zach Dundas. The Great Detective: The amazing rise and immortal life of Sherlock Holmes. Boston: Houghton Mifflin Harcourt, 2015, hardcover, $26 (336p, ISBN 978-0-544-21404-0, e-book $15.95 (2378 KB, ISBN 978-0-544-22020-1, ASIN B00LZ7GP6U. Nadine Farghaly, ed. Gender and the modern Sherlock Holmes: Essays on film and television adaptations since 2009. Jefferson, NC: McFarland, 2015, paperback, $35 (260p, ISBN 978-0-786-49459-0, e-book $9.99 (3353 KB, ISBN 978-1-4766-2281-1, ASIN B019WQQEY8. Alex Werner, ed. Sherlock Holmes: The man who never lived and will never die. London: Ebury Press, 2014, hardcover, £25 (256p, ISBN 978-0-09-195872-5, e-book £12.99, ISBN 978-1-47-350264-2.

  20. Fitz-Hugh-Curtis综合征在输卵管妊娠和不孕中的发生率及其意义%EXPLORATION ON INCIDENCE OF FITZ-HUGH-CURTIS SYNDROME IN TUBAL PREGNANCY AND TUBAL INFERTILITY

    Institute of Scientific and Technical Information of China (English)

    左绪磊

    2003-01-01

    目的:了解Fitz-Hugh-Curtis综合征在输卵管妊娠和输卵管不孕中的发生率,探讨它们在输卵管妊娠和输卵管不孕发生中的作用.方法:在腹腔镜检查和治疗妇科疾病时,确诊Fitz-Hugh-Curtis综合征遗留的典型病理改变和输卵管周围炎性病变.肿瘤、多囊卵巢综合征、子宫肌瘤等非输卵管炎性疾病患者作为对照组.结果:在109例输卵管妊娠患者中,发现慢性肝周围炎15例(13.8%),升结肠-腹壁粘连10例(9.2%),单纯输卵管周围炎性粘连24例(20.2%).而在112例对照组患者中,发现慢性肝周围炎患者2例(1.8%),升结肠-腹壁粘连患者2例(1.8%),输卵管周围炎性粘连患者2例(1.8%).与对照组相比,输卵管妊娠中肝周围炎发生率明显高于对照组(P<0.01),升结肠-腹壁粘连发生率也高于对照组(P<0.05).在20例经腹腔镜检查诊断为输卵管不孕的患者中,发现肝周围炎5例(25%),未发现升结肠-腹壁粘连.与对照组相比,输卵管性不孕患者中肝周围炎发生率明显高于对照组,差别有极显著意义P<0.001).结论:Fitz-Hugh-Curtis综合征在输卵管妊娠和不孕患者中的发生率与国外接近.肝周围炎、升结肠-腹壁粘连从侧面反映了盆腔炎性疾病在输卵管妊娠和输卵管不孕中起着重要作用.

  1. Destruction of the Fractional Quantum Hall Effect by Disorder

    Science.gov (United States)

    Laughlin, R. B.

    1985-07-01

    It is suggested that Hall steps in the fractional quantum Hall effect are physically similar to those in the ordinary quantum Hall effect. This proposition leads to a simple scaling diagram containing a new type of fixed point, which is identified with the destruction of the fractional states by disorder. 15 refs., 3 figs.

  2. Digital technology impacts on the Arnhem transfer hall structural design

    NARCIS (Netherlands)

    Van de Straat, R.; Hofman, S.; Coenders, J.L.; Paul, J.C.

    2015-01-01

    The new Transfer Hall in Arnhem is one of the key projects to prepare the Dutch railways for the increased future demands for capacity. UNStudio developed a master plan in 1996 for the station area of which the completion of the Transfer Hall in 2015 will be a final milestone. The Transfer Hall is a

  3. New type of magnetization equipment using a commercial Hall sensor

    Science.gov (United States)

    Nishioka, T.; Sato, N. K.

    2004-05-01

    We have developed a new method of the magnetization measurement using a commercial Hall sensor (Hall magnetometer), which enables us to measure the static magnetization very easily at temperatures as low as about 0.1 K and under pressure. We describe specifications of the Hall magnetometer, and show results of the magnetization measurement for UGe 2 as an example.

  4. Towards a Better Understanding of the Anomalous Hall Effect

    Science.gov (United States)

    Yue, Di; Jin, Xiaofeng

    2017-01-01

    Recent experimental efforts to identify the intrinsic and extrinsic contributions in the anomalous Hall effect are reviewed. Benefited from the experimental control of artificial impurity density in single crystalline magnetic thin films, a comprehensive physical picture of the anomalous Hall effect involving multiple competing scattering processes has been established. Some new insights into the microscopic mechanisms of the anomalous Hall effect are discussed.

  5. Accurate micro Hall effect measurements on scribe line pads

    DEFF Research Database (Denmark)

    Østerberg, Frederik Westergaard; Petersen, Dirch Hjorth; Wang, Fei

    2009-01-01

    Hall mobility and sheet carrier density are important parameters to monitor in advanced semiconductor production. If micro Hall effect measurements are done on small pads in scribe lines, these parameters may be measured without using valuable test wafers. We report how Hall mobility can...

  6. Parametric Investigations of Non-Conventional Hall Thruster

    Energy Technology Data Exchange (ETDEWEB)

    Raitses, Y.; Fisch, N.J.

    2001-01-12

    Hall thrusters might better scale to low power with non-conventional geometry. A 9 cm cylindrical, ceramic-channel, Hall thruster with a cusp-type magnetic field distribution has been investigated. It exhibits discharge characteristics similar to conventional coaxial Hall thrusters, but does not expose as much channel surface. Significantly, its operation is not accompanied by large amplitude discharge low frequency oscillations.

  7. Digital technology impacts on the Arnhem transfer hall structural design

    NARCIS (Netherlands)

    Van de Straat, R.; Hofman, S.; Coenders, J.L.; Paul, J.C.

    2015-01-01

    The new Transfer Hall in Arnhem is one of the key projects to prepare the Dutch railways for the increased future demands for capacity. UNStudio developed a master plan in 1996 for the station area of which the completion of the Transfer Hall in 2015 will be a final milestone. The Transfer Hall is a

  8. Improved Hall-Effect Sensors For Magnetic Memories

    Science.gov (United States)

    Wu, Jiin-Chuan; Stadler, Henry L.; Katti, Romney R.; Chen, Y. C.; Bhattacharya, Pallab K.

    1993-01-01

    High-electron-mobility sensor films deposited on superlattice buffer (strain) layers. Improved Hall-effect sensors offer combination of adequate response and high speed needed for use in micromagnet/Hall-effect random-access memories. Hall-effect material chosen for use in sensors is InAs.

  9. Inertial-Hall effect: the influence of rotation on the Hall conductivity

    Science.gov (United States)

    Brandão, Julio E.; Moraes, F.; Cunha, M. M.; Lima, Jonas R. F.; Filgueiras, C.

    Inertial effects play an important role in classical mechanics but have been largely overlooked in quantum mechanics. Nevertheless, the analogy between inertial forces on mass particles and electromagnetic forces on charged particles is not new. In this paper, we consider a rotating non-interacting planar two-dimensional electron gas with a perpendicular uniform magnetic field and investigate the effects of the rotation in the Hall conductivity. The rotation introduces a shift and a split in the Landau levels. As a consequence of the break of the degeneracy, the counting of the states fully occupied below the Fermi energy increases, tuning the Hall quantization steps. The rotation also changes the quantum Hall plateau widths. Additionally, we find the Hall quantization steps as a function of rotation at a fixed value of the magnetic field.

  10. Prospect of quantum anomalous Hall and quantum spin Hall effect in doped kagome lattice Mott insulators

    Science.gov (United States)

    Guterding, Daniel; Jeschke, Harald O.; Valentí, Roser

    2016-05-01

    Electronic states with non-trivial topology host a number of novel phenomena with potential for revolutionizing information technology. The quantum anomalous Hall effect provides spin-polarized dissipation-free transport of electrons, while the quantum spin Hall effect in combination with superconductivity has been proposed as the basis for realizing decoherence-free quantum computing. We introduce a new strategy for realizing these effects, namely by hole and electron doping kagome lattice Mott insulators through, for instance, chemical substitution. As an example, we apply this new approach to the natural mineral herbertsmithite. We prove the feasibility of the proposed modifications by performing ab-initio density functional theory calculations and demonstrate the occurrence of the predicted effects using realistic models. Our results herald a new family of quantum anomalous Hall and quantum spin Hall insulators at affordable energy/temperature scales based on kagome lattices of transition metal ions.

  11. Prospect of quantum anomalous Hall and quantum spin Hall effect in doped kagome lattice Mott insulators.

    Science.gov (United States)

    Guterding, Daniel; Jeschke, Harald O; Valentí, Roser

    2016-05-17

    Electronic states with non-trivial topology host a number of novel phenomena with potential for revolutionizing information technology. The quantum anomalous Hall effect provides spin-polarized dissipation-free transport of electrons, while the quantum spin Hall effect in combination with superconductivity has been proposed as the basis for realizing decoherence-free quantum computing. We introduce a new strategy for realizing these effects, namely by hole and electron doping kagome lattice Mott insulators through, for instance, chemical substitution. As an example, we apply this new approach to the natural mineral herbertsmithite. We prove the feasibility of the proposed modifications by performing ab-initio density functional theory calculations and demonstrate the occurrence of the predicted effects using realistic models. Our results herald a new family of quantum anomalous Hall and quantum spin Hall insulators at affordable energy/temperature scales based on kagome lattices of transition metal ions.

  12. The magneto-Hall difference and the planar extraordinary Hall balance

    Directory of Open Access Journals (Sweden)

    S. L. Zhang

    2016-04-01

    Full Text Available The extraordinary Hall balance (EHB is a general device concept that harnesses the net extraordinary Hall effect (EHE arising from two independent magnetic layers, which are electrically in parallel. Different EHB behavior can be achieved by tuning the strength and type of interlayer coupling, i.e., ferromagnetic or antiferromagnetic of varying strength, allowing for logic and memory applications. The physics of the EHE in such a multilayered systems, especially the interface-induced effect, will be discussed. A discrepancy between the magnetization and the Hall effect, called the magneto-Hall difference (MHD is found, which is not expected in conventional EHE systems. By taking advantage of the MHD effect, and by optimizing the materials structure, magnetoresistance ratios in excess of 40,000% can be achieved at room-temperature. We present a new design, the planar EHB, which has the potential to achieve significantly larger magnetoresistance ratios.

  13. The magneto-Hall difference and the planar extraordinary Hall balance

    Science.gov (United States)

    Zhang, S. L.; Hesjedal, T.

    2016-04-01

    The extraordinary Hall balance (EHB) is a general device concept that harnesses the net extraordinary Hall effect (EHE) arising from two independent magnetic layers, which are electrically in parallel. Different EHB behavior can be achieved by tuning the strength and type of interlayer coupling, i.e., ferromagnetic or antiferromagnetic of varying strength, allowing for logic and memory applications. The physics of the EHE in such a multilayered systems, especially the interface-induced effect, will be discussed. A discrepancy between the magnetization and the Hall effect, called the magneto-Hall difference (MHD) is found, which is not expected in conventional EHE systems. By taking advantage of the MHD effect, and by optimizing the materials structure, magnetoresistance ratios in excess of 40,000% can be achieved at room-temperature. We present a new design, the planar EHB, which has the potential to achieve significantly larger magnetoresistance ratios.

  14. Inertial-Hall effect: the influence of rotation on the Hall conductivity

    Directory of Open Access Journals (Sweden)

    Julio E. Brandão

    2015-01-01

    Full Text Available Inertial effects play an important role in classical mechanics but have been largely overlooked in quantum mechanics. Nevertheless, the analogy between inertial forces on mass particles and electromagnetic forces on charged particles is not new. In this paper, we consider a rotating non-interacting planar two-dimensional electron gas with a perpendicular uniform magnetic field and investigate the effects of the rotation in the Hall conductivity. The rotation introduces a shift and a split in the Landau levels. As a consequence of the break of the degeneracy, the counting of the states fully occupied below the Fermi energy increases, tuning the Hall quantization steps. The rotation also changes the quantum Hall plateau widths. Additionally, we find the Hall quantization steps as a function of rotation at a fixed value of the magnetic field.

  15. Prospect of quantum anomalous Hall and quantum spin Hall effect in doped kagome lattice Mott insulators

    Science.gov (United States)

    Guterding, Daniel; Jeschke, Harald O.; Valentí, Roser

    2016-01-01

    Electronic states with non-trivial topology host a number of novel phenomena with potential for revolutionizing information technology. The quantum anomalous Hall effect provides spin-polarized dissipation-free transport of electrons, while the quantum spin Hall effect in combination with superconductivity has been proposed as the basis for realizing decoherence-free quantum computing. We introduce a new strategy for realizing these effects, namely by hole and electron doping kagome lattice Mott insulators through, for instance, chemical substitution. As an example, we apply this new approach to the natural mineral herbertsmithite. We prove the feasibility of the proposed modifications by performing ab-initio density functional theory calculations and demonstrate the occurrence of the predicted effects using realistic models. Our results herald a new family of quantum anomalous Hall and quantum spin Hall insulators at affordable energy/temperature scales based on kagome lattices of transition metal ions. PMID:27185665

  16. Hall instability of solar flux tubes

    CERN Document Server

    Pandey, B P

    2011-01-01

    The magnetic network which consists of vertical flux tubes located in intergranular lanes is dominated by Hall drift in the photosphere-lower chromosphere region ($\\lesssim 1\\,{Mm}$). In the internetwork regions, Hall drift dominates above $0.25\\,{Mm}$ in the photosphere and below $2.5\\,{Mm}$ in the chromosphere. Although Hall drift does not cause any dissipation in the ambient plasma, it can destabilise flux tubes and magnetic elements in the presence of an azimuthal shear flow, which destabilises whistler waves. The physical mechanism of this instability is quite simple: the shear flow twists the radial magnetic field and generates azimuthal field; torsional oscillations of the azimuthal field in turn generates the radial field completing a feedback loop. The maximum growth rate of the Hall instability is proportional to the absolute value of the shear gradient and is dependent on the ambient diffusivity. The diffusivity also determines the cut--off wavenumber which is narrower for the stronger fields. We a...

  17. Room acoustic properties of concert halls

    DEFF Research Database (Denmark)

    Gade, Anders Christian

    1996-01-01

    A large database of values of various room acoustic parameters has provided the basis for statistical analyses of how and how much the acoustic properties of concert halls are influenced by their size, shape, and absorption area (as deduced from measured reverberation time). The data have been...

  18. Acoustics in rock and pop music halls

    DEFF Research Database (Denmark)

    Larsen, Niels Werner; Thompson, Eric Robert; Gade, Anders Christian

    2007-01-01

    The existing body of literature regarding the acoustic design of concert halls has focused almost exclusively on classical music, although there are many more performances of rhythmic music, including rock and pop. Objective measurements were made of the acoustics of twenty rock music venues...

  19. Anomalous Hall Effect for chiral fermions

    CERN Document Server

    Zhang, P -M

    2014-01-01

    Semiclassical chiral fermions manifest the anomalous spin-Hall effect: when put into a pure electric field, they suffer a side jump, analogous to what happens to their massive counterparts in non-commutative mechanics. The transverse shift is consistent with the conservation of the angular momentum. In a pure magnetic field a cork-screw-like, spiraling motion is found.

  20. Supersymmetry in the Fractional Quantum Hall Regime

    CERN Document Server

    Sagi, Eran

    2016-01-01

    Supersymmetry (SUSY) is a symmetry transforming bosons to fermions and vice versa. Indications of its existence have been extensively sought after in high-energy experiments. However, signatures of SUSY have yet to be detected. In this manuscript we propose a condensed matter realization of SUSY on the edge of a Read-Rezayi quantum Hall state, given by filling factors of the form $\

  1. Hall Effect Thruster Ground Testing Challenges

    Science.gov (United States)

    2009-08-18

    conditional stability of the inverted pendulum thrust stand provides improved measurement sensitivity.5 With the displacement of the inverted pendulum...July 2005. 12Samiento, C., “RHETT2/ EPDM Hall Thruster Propulsion System Electromagnetic Compatability Evaluation,” Proceed- ings of the 25th

  2. Development and applications of mesoscopic hall microprobes

    NARCIS (Netherlands)

    Novoselov, Konstantin S.

    2004-01-01

    This thesis is devoted to the further development of the local Hall magnetometery technique, and its application for studying ferromagnetic domain wall propagation on the sub-atomic scale. First the ballistic electron transport in a strong, non-uniform magnetic field is discussed. Than a possible in

  3. Fractional Quantization of the Hall Effect

    Science.gov (United States)

    Laughlin, R. B.

    1984-02-27

    The Fractional Quantum Hall Effect is caused by the condensation of a two-dimensional electron gas in a strong magnetic field into a new type of macroscopic ground state, the elementary excitations of which are fermions of charge 1/m, where m is an odd integer. A mathematical description is presented.

  4. Moderate positive spin Hall angle in uranium

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Simranjeet; Anguera, Marta; Barco, Enrique del, E-mail: delbarco@ucf.edu, E-mail: cwmsch@rit.edu [Department of Physics, University of Central Florida, Orlando, Florida 32816 (United States); Springell, Ross [H. H. Will Laboratory, University of Bristol, Bristol BS2 8BS (United Kingdom); Miller, Casey W., E-mail: delbarco@ucf.edu, E-mail: cwmsch@rit.edu [School of Chemistry and Materials Science, Rochester Institute of Technology, Rochester, New York 14623 (United States)

    2015-12-07

    We report measurements of spin pumping and the inverse spin Hall effect in Ni{sub 80}Fe{sub 20}/uranium bilayers designed to study the efficiency of spin-charge interconversion in a super-heavy element. We employ broad-band ferromagnetic resonance on extended films to inject a spin current from the Ni{sub 80}Fe{sub 20} (permalloy) into the uranium layer, which is then converted into an electric field by the inverse spin Hall effect. Surprisingly, our results suggest a spin mixing conductance of order 2 × 10{sup 19} m{sup −2} and a positive spin Hall angle of 0.004, which are both merely comparable with those of several transition metals. These results thus support the idea that the electronic configuration may be at least as important as the atomic number in governing spin pumping across interfaces and subsequent spin Hall effects. In fact, given that both the magnitude and the sign are unexpected based on trends in d-electron systems, materials with unfilled f-electron orbitals may hold additional exploration avenues for spin physics.

  5. Dust exposure in indoor climbing halls.

    Science.gov (United States)

    Weinbruch, Stephan; Dirsch, Thomas; Ebert, Martin; Hofmann, Heiko; Kandler, Konrad

    2008-05-01

    The use of hydrated magnesium carbonate hydroxide (magnesia alba) for drying the hands is a strong source for particulate matter in indoor climbing halls. Particle mass concentrations (PM10, PM2.5 and PM1) were measured with an optical particle counter in 9 indoor climbing halls and in 5 sports halls. Mean values for PM10 in indoor climbing halls are generally on the order of 200-500 microg m(-3). For periods of high activity, which last for several hours, PM10 values between 1000 and 4000 microg m(-3) were observed. PM(2.5) is on the order of 30-100 microg m(-3) and reaches values up to 500 microg m(-3), if many users are present. In sports halls, the mass concentrations are usually much lower (PM10 sport in which magnesia alba is also used) similar dust concentrations as for indoor climbing were observed. The size distribution and the total particle number concentration (3.7 nm-10 microm electrical mobility diameter) were determined in one climbing hall by an electrical aerosol spectrometer. The highest number concentrations were between 8000 and 12 000 cm(-3), indicating that the use of magnesia alba is no strong source for ultrafine particles. Scanning electron microscopy and energy-dispersive X-ray microanalysis revealed that virtually all particles are hydrated magnesium carbonate hydroxide. In-situ experiments in an environmental scanning electron microscope showed that the particles do not dissolve at relative humidities up to 100%. Thus, it is concluded that solid particles of magnesia alba are airborne and have the potential to deposit in the human respiratory tract. The particle mass concentrations in indoor climbing halls are much higher than those reported for schools and reach, in many cases, levels which are observed for industrial occupations. The observed dust concentrations are below the current occupational exposure limits in Germany of 3 and 10 mg m(-3) for respirable and inhalable dust. However, the dust concentrations exceed the German guide

  6. The Magneto-Hall Difference and the Planar Extraordinary Hall Balance

    OpenAIRE

    S. L. Zhang; Hesjedal, T.

    2016-01-01

    The extraordinary Hall balance (EHB) is a general device concept that harnesses the net extraordinary Hall effect (EHE) arising from two independent magnetic layers, which are electrically in parallel. Different EHB behavior can be achieved by tuning the strength and type of interlayer coupling, i.e., ferromagnetic or antiferromagnetic of varying strength, allowing for logic and memory applications. The physics of the EHE in such a multilayered systems, especially the interface-induced effect...

  7. Topological honeycomb magnon Hall effect: A calculation of thermal Hall conductivity of magnetic spin excitations

    Science.gov (United States)

    Owerre, S. A.

    2016-07-01

    Quite recently, the magnon Hall effect of spin excitations has been observed experimentally on the kagome and pyrochlore lattices. The thermal Hall conductivity κxy changes sign as a function of magnetic field or temperature on the kagome lattice, and κxy changes sign upon reversing the sign of the magnetic field on the pyrochlore lattice. Motivated by these recent exciting experimental observations, we theoretically propose a simple realization of the magnon Hall effect in a two-band model on the honeycomb lattice. The magnon Hall effect of spin excitations arises in the usual way via the breaking of inversion symmetry of the lattice, however, by a next-nearest-neighbour Dzyaloshinsky-Moriya interaction. We find that κxy has a fixed sign for all parameter regimes considered. These results are in contrast to the Lieb, kagome, and pyrochlore lattices. We further show that the low-temperature dependence on the magnon Hall conductivity follows a T2 law, as opposed to the kagome and pyrochlore lattices. These results suggest an experimental procedure to measure thermal Hall conductivity within a class of 2D honeycomb quantum magnets and ultracold atoms trapped in a honeycomb optical lattice.

  8. Comparison of secondary islands in collisional reconnection to Hall reconnection.

    Science.gov (United States)

    Shepherd, L S; Cassak, P A

    2010-07-02

    Large-scale resistive Hall-magnetohydrodynamic simulations of the transition from Sweet-Parker (collisional) to Hall (collisionless) magnetic reconnection are presented; the first to separate secondary islands from collisionless effects. Three main results are described. There exists a regime with secondary islands but without collisionless effects, and the reconnection rate is faster than Sweet-Parker, but significantly slower than Hall reconnection. This implies that secondary islands do not cause the fastest reconnection rates. The onset of Hall reconnection ejects secondary islands from the vicinity of the X line, implying that energy is released more rapidly during Hall reconnection. Coronal applications are discussed.

  9. Parallel Hall effect from 3D single-component metamaterials

    CERN Document Server

    Kern, Christian; Wegener, Martin

    2015-01-01

    We propose a class of three-dimensional metamaterial architectures composed of a single doped semiconductor (e.g., n-Si) in air or vacuum that lead to unusual effective behavior of the classical Hall effect. Using an anisotropic structure, we numerically demonstrate a Hall voltage that is parallel---rather than orthogonal---to the external static magnetic-field vector ("parallel Hall effect"). The sign of this parallel Hall voltage can be determined by a structure parameter. Together with the previously demonstrated positive or negative orthogonal Hall voltage, we demonstrate four different sign combinations

  10. Positive Intervention for Serious Behavior Problems: Best Practices in Implementing the Hughes Bill (A.B. 2586) and the Positive Behavioral Intervention Regulations.

    Science.gov (United States)

    Wright, Diana Browning; Gurman, Harvey B.

    This manual provides guidelines to educators attempting to comply with California's Hughes Bill, which is intended to ensure the rights of special education students to have positive behavioral intervention plans designed to bring lasting behavioral changes without interventions that cause pain or trauma. An introductory chapter summarizes the…

  11. Influence of spatially modified tissue on atrial fibrillation patterns: Insight from solutions of the FitzHugh-Nagumo equations

    CERN Document Server

    Lenk, Claudia; Maass, Philipp

    2010-01-01

    We study the interplay between traveling action potentials and spatial inhomogeneities in the FitzHugh-Nagumo model to investigate possible mechanisms for the occurrence of fibrillatory states in the atria of the heart. Different dynamical patterns such as ectopic foci, localized and meandering spiral waves are found depending on the characteristics of the inhomogeneities. Their appearance in dependence of the size and strength of the inhomogeneities is quantified by phase diagrams. Furthermore it is shown that regularly paced waves in a region R, that is connected by a small bridge connection to another region L with perturbing waves emanating from an additional pacemaker, can be strongly disturbed, so that a fibrillatory state emerges in region R after a transient time interval. This finding supports conjectures that fibrillatory states in the right atrium can be induced by self-excitatory pacemakers in the left atrium.

  12. Frédéric Sylvanise. Langston Hughes, poète jazz, poète blues

    Directory of Open Access Journals (Sweden)

    Hélène CHRISTOL

    2011-03-01

    Full Text Available La Renaissance de Harlem a été redécouverte en France au début du XXIe siècle, grâce à l’organisation de manifestations publiques et universitaires ainsi que la publication de nombreuses études qui « revisitent » la période et les œuvres de ses écrivains et de ses artistes.  L’ouvrage de Frédéric Sylvanise, Langston Hughes, poète jazz, poète blues, publié par les éditions de l’ENS en 2009, apporte sa pierre à cet édifice critique puisqu’il se penche sur certains recueils de poésie de cet écri...

  13. Stability Switches and Hopf Bifurcation in a Coupled FitzHugh-Nagumo Neural System with Multiple Delays

    Directory of Open Access Journals (Sweden)

    Shengwei Yao

    2014-01-01

    Full Text Available A FitzHugh-Nagumo (FHN neural system with multiple delays has been proposed. The number of equilibrium point is analyzed. It implies that the neural system exhibits a unique equilibrium and three ones for the different values of coupling weight by employing the saddle-node bifurcation of nontrivial equilibrium point and transcritical bifurcation of trivial one. Further, the stability of equilibrium point is studied by analyzing the corresponding characteristic equation. Some stability criteria involving the multiple delays and coupling weight are obtained. The results show that the neural system exhibits the delay-independence and delay-dependence stability. Increasing delay induces the stability switching between resting state and periodic activity in some parameter regions of coupling weight. Finally, numerical simulations are taken to support the theoretical results.

  14. Diagnostics Systems for Permanent Hall Thrusters Development

    Science.gov (United States)

    Ferreira, Jose Leonardo; Soares Ferreira, Ivan; Santos, Jean; Miranda, Rodrigo; Possa, M. Gabriela

    This work describes the development of Permanent Magnet Hall Effect Plasma Thruster (PHALL) and its diagnostic systems at The Plasma Physics Laboratory of University of Brasilia. The project consists on the construction and characterization of plasma propulsion engines based on the Hall Effect. Electric thrusters have been employed in over 220 successful space missions. Two types stand out: the Hall-Effect Thruster (HET) and the Gridded Ion Engine (GIE). The first, which we deal with in this project, has the advantage of greater simplicity of operation, a smaller weight for the propulsion subsystem and a longer shelf life. It can operate in two configurations: magnetic layer and anode layer, the difference between the two lying in the positioning of the anode inside the plasma channel. A Hall-Effect Thruster-HET is a type of plasma thruster in which the propellant gas is ionized and accelerated by a magneto hydrodynamic effect combined with electrostatic ion acceleration. So the essential operating principle of the HET is that it uses a J x B force and an electrostatic potential to accelerate ions up to high speeds. In a HET, the attractive negative charge is provided by electrons at the open end of the Thruster instead of a grid, as in the case of the electrostatic ion thrusters. A strong radial magnetic field is used to hold the electrons in place, with the combination of the magnetic field and the electrostatic potential force generating a fast circulating electron current, the Hall current, around the axis of the Thruster, mainly composed by drifting electrons in an ion plasma background. Only a slow axial drift towards the anode occurs. The main attractive features of the Hall-Effect Thruster are its simple design and operating principles. Most of the Hall-Effect Thrusters use electromagnet coils to produce the main magnetic field responsible for plasma generation and acceleration. In this paper we present a different new concept, a Permanent Magnet Hall

  15. The Hall Algebra of Cyclic Serial Algebra

    Institute of Scientific and Technical Information of China (English)

    郭晋云

    1994-01-01

    In this paper, orders <1 and <2 on ((Z)+)nm are introduced and also regarded as orders on the isomorphism classes of finite modules of finite .cyclic algebra R with n simple modules and all the indecomposable projective modules have length m through a one-to-one correspondence between ((Z)+)nm and the isomorphism classes of finite R modules. Using this we prove that the Hall algebra of a cyclic serial algebra is identified with its Loewy subalgebra, and its rational extension has a basis of BPW type, and is a (((Z)+)nm, <2) filtered ring with the associated graded ring as an iterated skew polynomial ring. These results are also generalized to the Hall algebra of a tube over a finite field.

  16. Three halls for music performance in Chile

    Science.gov (United States)

    Delannoy, Jaime; Heuffemann, Carolina; Ramirez, Daniel; Galvez, Fernando

    2002-11-01

    The primary purpose of this work was to investigate about the present acoustic conditions of used architectonic spaces in Santiago of Chile for orchestras of classic music performance. The studied halls were three: Aula Magna Universidad de Santiago, Teatro Municipal de Nunoa, and Teatro Baquedano. The used methodology was based on studies made by L. Beranek, M. Barron, among others, in concert halls worldwide. As it guides, for the measurement procedure, physical parameters RT, EDT, C50, C80, LF, BR, G, U50 were evaluated according to norm ISO 3382. On the other hand, it has been defined, to proposal way, a questionnaire of subjective valuation directed to musicians, specialized conductors, and listeners.

  17. Acoustics in rock and pop music halls

    DEFF Research Database (Denmark)

    Larsen, Niels Werner; Thompson, Eric Robert; Gade, Anders Christian

    2007-01-01

    The existing body of literature regarding the acoustic design of concert halls has focused almost exclusively on classical music, although there are many more performances of rhythmic music, including rock and pop. Objective measurements were made of the acoustics of twenty rock music venues...... in Denmark and a questionnaire was used in a subjective assessment of those venues with professional rock musicians and sound engineers. Correlations between the objective and subjective results lead, among others, to a recommendation for reverberation time as a function of hall volume. Since the bass...... frequency sounds are typically highly amplified, they play an important role in the subjective ratings and the 63-Hz-band must be included in objective measurements and recommendations....

  18. Judy Estes Hall (1940-2015).

    Science.gov (United States)

    Sammons, Morgan T; Boucher, Andrew

    2016-01-01

    Presents an obituary for Judy Estes Hall, who passed away on November 24, 2015. Hall served as the Executive Officer of the National Register of Health Service Psychologists until her retirement in 2013. She is a recognized expert in the development of education and training standards for the profession of psychology, she also made significant contributions in the field of international psychology, where she was a renowned expert in cross-national credentialing and an advocate for commonality in licensing standards. She was the coauthor of one edited volume and author of more than 60 journal articles, book chapters, and professional publications. A passionate advocate for the advancement of women in psychology, a devoted mother and grandmother, a connoisseur of wine and international traveler extraordinaire, she touched the personal and professional lives of many. (PsycINFO Database Record

  19. Hall Scrambling on Black Hole Horizon

    CERN Document Server

    Fischler, Willy

    2015-01-01

    We explore the effect of the electrodynamics $\\theta$-angle on the macroscopic properties of black hole horizons. Using only classical Einstein-Maxwell-Chern-Simons theory in (3+1)-dimensions, in the form of the membrane paradigm, we show that in the presence of the $\\theta$-term, a black hole horizon behaves as a Hall conductor, for an observer hovering outside. We study how localized perturbations created on the stretched horizon scramble on the horizon by dropping a charged particle. We show that the $\\theta$-angle affects the way perturbations scramble on the horizon, in particular, it introduces vortices without changing the scrambling time. This Hall scrambling of information is also expected to occur on cosmological horizons.

  20. Music hall Markneukirchen; Musikhalle in Markneukirchen

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1996-01-01

    The article presents the new building of the music hall Markneukirchen. From the planned use of the building result very high demands on the ventilation system in order to keep to a sound power level of less than 30 dB(A) in the hall. The building services are dealt with using numerous flowsheets and diagrams: Heat supply, ventilation system, sanitary system, building management, instrumentation and control, electric and lighting systems. (BWI) [Deutsch] Der vorliegende Beitrag stellt den Neubau der Musikhalle Markneukirchen vor. Durch das Nutzungskonzept ergeben sich fuer die Einhaltung eines Schalleistungspegels von weniger als 30 dB(A) im Saalbereich an die Lueftungsanlage sehr hohe Ansprueche. Es werden die raumlufttechnischen Anlagen anhand zahlreicher Flussbilder und Abbildungen vorgestellt: Waermeversorgung, Lueftungstechnik, Sanitaertechnik, Gebaeudeleit- und MSR-Technik, Elektro- und Lichttechnik. (BWI)

  1. SPS beam to the West Hall

    CERN Multimedia

    1976-01-01

    One of the two target stations feeding the West Hall (see Annual Report 1976). After the proton beam was split into three branches, the outer two were directed on to targets in the cast iron shielding box, the centre one passing through the box to another target station downstream. Five different targets could be put in each beam, controlled by the mechanism seen on top.

  2. Geometric Photonic Spin Hall Effect with Metapolarization

    OpenAIRE

    2014-01-01

    We develop a geometric photonic spin Hall effect (PSHE) which manifests as spin-dependent shift in momentum space. It originates from an effective space-variant Pancharatnam-Berry (PB) phase created by artificially engineering the polarization distribution of the incident light. Unlikely the previously reported PSHE involving the light-matter interaction, the resulting spin-dependent splitting in the geometric PSHE is purely geometrically depend upon the polarization distribution of light whi...

  3. Thermal Characterization of a Hall Effect Thruster

    Science.gov (United States)

    2008-03-01

    Material Curie Temperature Iron 770 °C Nickel 358 °C Cobalt 1130 °C Gadolinium 20 °C Terfenol 380-430 °C Alnico 850 °C Hard Ferrites 400-700...C Barium Ferrite 450 °C Hall Effect thrusters generally use iron magnets with a Curie temperature of 770 °C. Decreasing the magnetic strength

  4. Electron-wall Interaction in Hall Thrusters

    Energy Technology Data Exchange (ETDEWEB)

    Y. Raitses; D. Staack; M. Keidar; N.J. Fisch

    2005-02-11

    Electron-wall interaction effects in Hall thrusters are studied through measurements of the plasma response to variations of the thruster channel width and the discharge voltage. The discharge voltage threshold is shown to separate two thruster regimes. Below this threshold, the electron energy gain is constant in the acceleration region and therefore, secondary electron emission (SEE) from the channel walls is insufficient to enhance electron energy losses at the channel walls. Above this voltage threshold, the maximum electron temperature saturates.

  5. Homotopy arguments for quantized Hall conductivity

    CERN Document Server

    Richter, T

    2002-01-01

    Using the strong localization bounds obtained by the Aizenman-Molcanov method for a particle in a magnetic field and a disordered potential, we show that the zero-temperature Hall conductivity of a gas of such particles is quantized and constant as long as both Fermi energy and disorder coupling parameter vary in a region of strong localization of the corresponding two-dimensional phase diagram.

  6. Industrial steel hall with bridge grane

    OpenAIRE

    Jurejevčič, Nejc

    2016-01-01

    In introduction this diploma thesis describes all main characteristics of (single block)? industrial steel hall with bridge crane. Load arrangement on the supporting structure which covers general actions (snow load and wind action), self-weight and dynamic load of bridge crane was designed with moment resisting frame in transverse direction and frame with concentric diagonal bracing in longitudinual direction. Actions induced by crane bridge was considered in design of runway beam. Steel hal...

  7. The Hall D Physics Program at JLab

    Energy Technology Data Exchange (ETDEWEB)

    Leckey, John P. [Indiana U.

    2012-09-01

    GlueX is one of the flagship experiments of the 12 GeV era at the Thomas Jefferson National Accelerator Facility (JLab). The energy of the electron accelerator at JLab is presently undergoing an upgrade from 6 GeV to 12 GeV and a 4th experimental hall (Hall D) is being added. The GlueX experimental apparatus consists of a tagged coherent bremsstrahlung photon beam incident on a liquid hydrogen target. The photoproduced mesons, which are created inside of a 2.2 T solenoid, will then pass through a pair of drift chambers and eventually deposit their energy into either of two calorimeters, depending on their respective angles. GlueX will attempt to map out the light meson spectrum and search for meson-gluon hybrids to better understand the confinement of quarks and gluons in quantum chromodynamics (QCD). There is little data on the photoproduction of light mesons and the GlueX experiment will exceed the current photoproduction data by several orders of magnitude in the first year alone. Photoproduction is specifically well suited to search for meson-gluon hybrids because in the flux tube model the production cross-sections are higher for meson-gluon hybrids from photons, with the spins of the virtual quark-antiquark pair aligned, than from other sources such as pions, with the spins of the quark-antiquark pair anti-aligned. There are also other Hall D experiments proposed to look for physics beyond the Standard Model by studying Eta rare or forbidden decay channels such as eta to two neutral pions. The 12 GeV upgrade of the JLab accelerator and the complete physics program of Hall D will be presented.

  8. Views of the ATLAS experimental hall

    CERN Multimedia

    Maximilien Brice

    2005-01-01

    The shell of the ATLAS detector is seen from many angles within its cavernous underground hall. All of the eight huge toroid magnets have been installed and fixed in place. The core of the detector, the largest of its type in the world, will soon be filled with many different detector-elements to observe the results of proton-proton collisions at the LHC when it is turned on in 2008.

  9. Acoustics in rock and pop music halls

    DEFF Research Database (Denmark)

    Adelman-Larsen, Niels Werner; Thompson, Eric Robert; Gade, Anders Christian

    2007-01-01

    The existing body of literature regarding the acoustic design of concert halls has focused almost exclusively on classical music, although there are many more performances of rhythmic music, including rock and pop. Objective measurements were made of the acoustics of twenty rock music venues in D...... frequency sounds are typically highly amplified, they play an important role in the subjective ratings and the 63-Hz-band must be included in objective measurements and recommendations....

  10. SERVIR Town Hall - Connecting Space to Village

    Science.gov (United States)

    Limaye, Ashutosh S.; Searby, Nancy D.; Irwin, Daniel; Albers, Cerese

    2013-01-01

    SERVIR, a joint NASA-USAID project, strives to improve environmental decision making through the use of Earth observations, models, and geospatial technology innovations. SERVIR connects these assets with the needs of end users in Mesoamerica, East Africa, and Hindu Kush-Himalaya regions. This Town Hall meeting will engage the AGU community by exploring examples of connecting Space to Village with SERVIR science applications.

  11. A Magnetic Balance with Hall Effect Sensors

    Science.gov (United States)

    Sawada, Hideo; Kunimasu, Tetsuya; Suda, Shinichi; Mizoguti, Yasushi; Okada, Takumi

    Magnetic force acting on a model fixed at the center of the JAXA 60cm MSBS was measured with an industry manufactured balance system when MSBS control coil currents were varied. At the same time, magnetic field intensity was also measured with 11 Hall sensors, which were arranged around the MSBS test section. From relations between coil currents and its corresponding controlled magnetic forces, regressive curves were given and maximum deviation from the curves was evaluated. From relations between Hall sensor outputs and the magnetic forces, regressive curves and deviation were also obtained. Obtained results show Hall sensor outputs are much better indexes of balance than the coil currents. The maximum deviations were reduced to a half or one-third times as much as those evaluated using the control coil currents. However, when couples acting on the model are controlled, they are not effective to reduce hysteresis phenomenon in the relation. The deviation can be reduced by decreasing the range of calibration. Then, the error of the balance of the MSBS was reduced to about 1% of the calibration range.

  12. Hall measurements on InAs nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Bloemers, Christian; Grap, Thomas; Lepsa, Mihail I.; Gruetzmacher, Detlev; Lueth, Hans [Peter Gruenberg Institut (PGI-9), Forschungszentrum Juelich GmbH, 52425 Juelich (Germany); JARA - Fundamentals of Future Information Technology (Germany); Trellenkamp, Stefan [Peter Gruenberg Institut (PGI-8), Forschungszentrum Juelich GmbH, 52425 Juelich (Germany); JARA - Fundamentals of Future Information Technology (Germany); Schaepers, Thomas [Peter Gruenberg Institut (PGI-9), Forschungszentrum Juelich GmbH, 52425 Juelich (Germany); JARA - Fundamentals of Future Information Technology (Germany); II. Physikalisches Institut, RWTH Aachen, 52074 Aachen (Germany)

    2012-07-01

    In search of novel concepts for the realization of nanoelectronic devices, semiconductor nanowires grown by ''bottom-up'' techniques have shown great promise. Without any doubt, the knowledge about the free carrier concentration n{sub el} is crucial for the fabrication of such devices on the nanometer scale. The most common method to determine n{sub el} in nanowires is to utilize the field effect in a gate measurement setup. However, within this method, uncertainties such as the density of surface states between the nanowire and the dielectric material or the resulting nanowire capacitance influence results. Additionally, source and drain electrodes tend to screen the gate potential in devices of small size. Here we report on Hall measurements on InAs nanowires as an alternative method to determine n{sub el}. By electron beam lithography we are able to fabricate side contacts to single nanowires to realize a Hall-measurement geometry. The side contacts allow us to measure a Hall-voltage, from which we deduce the carrier concentration in the wires.

  13. Quantum anomalous Hall effect in real materials

    Science.gov (United States)

    Zhang, Jiayong; Zhao, Bao; Zhou, Tong; Yang, Zhongqin

    2016-11-01

    Under a strong magnetic field, the quantum Hall (QH) effect can be observed in two-dimensional electronic gas systems. If the quantized Hall conductivity is acquired in a system without the need of an external magnetic field, then it will give rise to a new quantum state, the quantum anomalous Hall (QAH) state. The QAH state is a novel quantum state that is insulating in the bulk but exhibits unique conducting edge states topologically protected from backscattering and holds great potential for applications in low-power-consumption electronics. The realization of the QAH effect in real materials is of great significance. In this paper, we systematically review the theoretical proposals that have been brought forward to realize the QAH effect in various real material systems or structures, including magnetically doped topological insulators, graphene-based systems, silicene-based systems, two-dimensional organometallic frameworks, quantum wells, and functionalized Sb(111) monolayers, etc. Our paper can help our readers to quickly grasp the recent developments in this field. Project supported by the National Basic Research Program of China (Grant No. 2011CB921803), the National Natural Science Foundation of China (Grant No. 11574051), the Natural Science Foundation of Shanghai, China (Grant No. 14ZR1403400), and Fudan High-end Computing Center, China.

  14. Generic superweak chaos induced by Hall effect.

    Science.gov (United States)

    Ben-Harush, Moti; Dana, Itzhack

    2016-05-01

    We introduce and study the "kicked Hall system" (KHS), i.e., charged particles periodically kicked in the presence of uniform magnetic (B) and electric (E) fields that are perpendicular to each other and to the kicking direction. We show that for resonant values of B and E and in the weak-chaos regime of sufficiently small nonintegrability parameter κ (the kicking strength), there exists a generic family of periodic kicking potentials for which the Hall effect from B and E significantly suppresses the weak chaos, replacing it by "superweak" chaos (SWC). This means that the system behaves as if the kicking strength were κ^{2} rather than κ. For E=0, SWC is known to be a classical fingerprint of quantum antiresonance, but it occurs under much less generic conditions, in particular only for very special kicking potentials. Manifestations of SWC are a decrease in the instability of periodic orbits and a narrowing of the chaotic layers, relative to the ordinary weak-chaos case. Also, for global SWC, taking place on an infinite "stochastic web" in phase space, the chaotic diffusion on the web is much slower than the weak-chaos one. Thus, the Hall effect can be relatively stabilizing for small κ. In some special cases, the effect is shown to cause ballistic motion for almost all parameter values. The generic global SWC on stochastic webs in the KHS appears to be the two-dimensional closest analog to the Arnol'd web in higher dimensional systems.

  15. Mobile technologies in the service of students' learning of mathematics: the example of game application A.L.E.X. in the context of a primary school in Cyprus

    Science.gov (United States)

    Kyriakides, Andreas O.; Meletiou-Mavrotheris, Maria; Prodromou, Theodosia

    2016-03-01

    This article reports on the main experiences gained from a 2-year study which incorporated A.L.E.X., an educational puzzle game available on iPad or Android tablet devices, within the primary school mathematics curriculum. The study took place in a public primary school, located in a rural area of Cyprus. The majority of its students come from low socioeconomic status families. Among the school community, a group of 15 pupils (eight boys and seven girls), aged 10-11 years old, was randomly selected to comprise the sample. The same group of students was visited twice within a period of 2 years, and a teaching intervention was organized. In both interventions, the application A.L.E.X. accompanied by a student worksheet constituted the main means of instruction. The worksheets were designed to integrate a technology with core mathematical ideas embedded in the national mathematics curriculum. Findings gained from the teaching intervention suggest that game apps hold a lot of promise as a tool for reforming mathematics education. While working with A.L.E.X., the children identified and processed mathematical themes that emerged spontaneously. They experienced unique emotions of surprise and enthusiasm regarding the existence of games with mathematical content that led them to acknowledge the pedagogical role that tablet devices could play. This helped them to broaden their fundamentally narrow viewpoint of mathematics as being primarily computation and arithmetic.

  16. Antiferromagnetic skyrmion crystals: Generation, topological Hall, and topological spin Hall effect

    Science.gov (United States)

    Göbel, Börge; Mook, Alexander; Henk, Jürgen; Mertig, Ingrid

    2017-08-01

    Skyrmions are topologically nontrivial, magnetic quasiparticles that are characterized by a topological charge. A regular array of skyrmions, a skyrmion crystal (SkX), features the topological Hall effect (THE) of electrons, which, in turn, gives rise to the Hall effect of the skyrmions themselves. It is commonly believed that antiferromagnetic skyrmion crystals (AFM-SkXs) lack both effects. In this Rapid Communication, we present a generally applicable method to create stable AFM-SkXs by growing a two-sublattice SkX onto a collinear antiferromagnet. As an example we show that both types of skyrmion crystals, conventional and antiferromagnetic, exist in honeycomb lattices. While AFM-SkXs with equivalent lattice sites do not show a THE, they exhibit a topological spin Hall effect. On top of this, AFM-SkXs on inequivalent sublattices exhibit a nonzero THE, which may be utilized in spintronics devices. Our theoretical findings call for experimental realization.

  17. Dissipationless spin-Hall current contribution in the extrinsic spin-Hall effect

    Institute of Scientific and Technical Information of China (English)

    Yan Yu-Zhen; Li Hui-Wu; Hu Liang-Bin

    2009-01-01

    This paper shows that a substantial amount of dissipationless spin-Hall current contribution may exist in the extrinsic spin-Hall effect, which originates from the spin-orbit coupling induced by the applied external electric field itself that drives the extrinsic spin-Hall effect in a nonmagnetic semiconductor (or metal). By assuming that the impurity density is in a moderate range such that the total scattering potential due to all randomly distributed impurities is a smooth function of the space coordinate, it is shown that this dissipationless contribution shall be of the same orders of magnitude as the usual extrinsic contribution from spin-orbit dependent impurity scatterings (or may even be larger than the latter one). The theoretical results obtained are in good agreement with recent relevant experimental results.

  18. A epistemologia de Hugh Lacey em diálogo com a Economia Feminista: neutralidade, objetividade e pluralismo Hugh Lacey's epistemology dialogs with feminist economy: neutrality, objectivity and pluralism

    Directory of Open Access Journals (Sweden)

    Brena Paula Magno Fernandez

    2008-08-01

    Full Text Available A Economia Feminista é um dos mais recentes programas de pesquisa em ciência econômica. Desde a publicação de Beyond Economic Man, organizado por Marianne Ferber e Julie Nelson,¹ ele vem se desenvolvendo com crescente força, sobretudo nos Estados Unidos. Entretanto, a pesquisa feminista, em geral, e a economia feminista, em particular, são freqüentemente consideradas como menos objetivas do que as pesquisas tradicionais, e isso porque estas últimas seriam livres de valores, enquanto as primeiras não. Após traçar algumas definições centrais da Economia Feminista, propomos, a partir do modelo crítico de Hugh Lacey,² que: i almejar a objetividade não significa defender uma metodologia isenta de influências valorativas, ii a neutralidade é (e deve ser defensável para o conjunto da prática científica e, finalmente, iii a defesa da pluralidade de abordagens científicas é o meio através do qual a neutralidade da ciência como uma prática social pode ser salvaguardada.Feminist Economics is one of the most recent research programs in economic science. Since the publication of Beyond Economic Man, edited by Ferber and Nelson (1993, it has been developed with increasing strength, especially in the United States. However, feminist researches in general and feminist economics in particular are often perceived to be less objective than conventional research, on the grounds that the latter would be value-neutral and the former would not. After drawing up some central definitions of Feminist Economics, we follow Hugh Lacey's critical model (1998, 1999 and propose that: i to aim for objectivity does not mean to defend a methodology that is free from axiological influences, ii neutrality is (and ought to be defensible for scientific practice as a whole, and finally, iii the defense of a plurality of scientific approaches is the way through which the neutrality of science as a social practice can be safeguarded.

  19. Commemorative Symposium on the Hall Effect and its Applications

    CERN Document Server

    Westgate, C

    1980-01-01

    In 1879, while a graduate student under Henry Rowland at the Physics Department of The Johns Hopkins University, Edwin Herbert Hall discovered what is now universally known as the Hall effect. A symposium was held at The Johns Hopkins University on November 13, 1979 to commemorate the lOOth anniversary of the discovery. Over 170 participants attended the symposium which included eleven in­ vited lectures and three speeches during the luncheon. During the past one hundred years, we have witnessed ever ex­ panding activities in the field of the Hall effect. The Hall effect is now an indispensable tool in the studies of many branches of condensed matter physics, especially in metals, semiconductors, and magnetic solids. Various components (over 200 million!) that utilize the Hall effect have been successfully incorporated into such devices as keyboards, automobile ignitions, gaussmeters, and satellites. This volume attempts to capture the important aspects of the Hall effect and its applications. It includes t...

  20. Basic Instrumentation for Hall A at Jefferson Jab

    Energy Technology Data Exchange (ETDEWEB)

    The Jefferson Lab Hall A Collaboration

    2003-07-01

    The instrumentation in Hall A at the JLab was designed to study electro- and photo-induced reactions at very high luminosity and good momentum and angular resolution for at least one of the reaction products. A collaboration of approximately 50 institutions from all over the world has actively contributed and participated in the design, construction and commissioning of the Hall A instrumentation. The basic Hall A equipment is described herein.

  1. Estimates of Quantities in a Hall Effect Geodynamo Theory

    Directory of Open Access Journals (Sweden)

    Annraoi M de Paor

    2008-01-01

    Full Text Available Currents, resistances, dynamo constant, Hall voltage coefficient and inductances are estimated for the author’s geodynamo theory incorporating the Hall Effect. It is concluded that the Hall Coefficient in the bulk liquid core of the Earth is approximately 1.512x10-1, orders of magnitude greater than in normal liquid metals. The ordering effect of enormous pressure is a possible cause.

  2. Estimates of quantities in a Hall effect geodynamo theory

    OpenAIRE

    Annraoi M de Paor

    2008-01-01

    Currents, resistances, dynamo constant, Hall voltage coefficient and inductances are estimated for the author’s geodynamo theory incorporating the Hall Effect. It is concluded that the Hall Coefficient in the bulk liquid core of the Earth is approximately 1.512x10-1, orders of magnitude greater than in normal liquid metals. The ordering effect of enormous pressure is a possible cause.

  3. Charge and Current in the Quantum Hall Matrix Model

    OpenAIRE

    2003-01-01

    We extend the quantum Hall matrix model to include couplings to external electric and magnetic fields. The associated current suffers from matrix ordering ambiguities even at the classical level. We calculate the linear response at low momenta -- this is unambigously defined. In particular, we obtain the correct fractional quantum Hall conductivity, and the expected density modulations in response to a weak and slowly varying magnetic field. These results show that the classical quantum Hall ...

  4. Hall effect in strongly correlated low dimensional systems

    OpenAIRE

    Leon Suros, Gladys Eliana; Berthod, Christophe; Giamarchi, Thierry

    2006-01-01

    We investigate the Hall effect in a quasi one-dimensional system made of weakly coupled Luttinger Liquids at half filling. Using a memory function approach, we compute the Hall coefficient as a function of temperature and frequency in the presence of umklapp scattering. We find a power-law correction to the free-fermion value (band value), with an exponent depending on the Luttinger parameter $K_{\\rho}$. At high enough temperature or frequency the Hall coefficient approaches the band value.

  5. Fabrication of a vector Hall sensor for magnetic microscopy

    Science.gov (United States)

    Gregušová, D.; Cambel, V.; Fedor, J.; Kúdela, R.; Šoltýs, J.; Lalinský, T.; Kostič, I.; Bending, S. J.

    2003-05-01

    We have developed a micromachined Hall sensor for scanning the entire magnetic field vector whose active dimensions are an order of magnitude smaller (˜5 μm) than the smallest existing vector field sensor. It is realized by patterning three Hall probes on the tilted faces of epitaxy-overgrown GaAs-based pyramidal-shaped mesa structures. Data from these "tilted" Hall probes are used to reconstruct the full magnetic field vector.

  6. Quantized Thermal Transport in the Fractional Quantum Hall Effect

    OpenAIRE

    Kane, C. L.; Fisher, Matthew P. A.

    1996-01-01

    We analyze thermal transport in the fractional quantum Hall effect (FQHE), employing a Luttinger liquid model of edge states. Impurity mediated inter-channel scattering events are incorporated in a hydrodynamic description of heat and charge transport. The thermal Hall conductance, $K_H$, is shown to provide a new and universal characterization of the FQHE state, and reveals non-trivial information about the edge structure. The Lorenz ratio between thermal and electrical Hall conductances {\\i...

  7. Pseudospectral Model for Hybrid PIC Hall-effect Thruster Simulation

    Science.gov (United States)

    2015-07-01

    1149. 8Goebel, D. M. and Katz, I., Fundamentals of Electric Propulsion : Ion and Hall Thrusters, John Wiley & Sons, Inc., 2008. 9Martin, R., J.W., K...Bilyeu, D., and Tran, J., “Dynamic Particle Weight Remapping in Hybrid PIC Hall -effect Thruster Simulation,” 34th Int. Electric Propulsion Conf...Paper 3. DATES COVERED (From - To) July 2015-July 2015 4. TITLE AND SUBTITLE Pseudospectral model for hybrid PIC Hall -effect thruster simulationect

  8. Vibrational and Stochastic Resonance in the FitzHugh-Nagumo Neural Model with Multiplicative and Additive Noise

    Institute of Scientific and Technical Information of China (English)

    HE Zheng-You; ZHOU Yu-Rong

    2011-01-01

    The vibrational resonance and stochastic resonance phenomena in the FitzHugh-Nagumo (FHN) neural model,driven by a high-frequency (HF) signal and a low-frequency (LF) signal and by coupled multiplicative and additive noises,is investigated.For the case that the frequency of the HF signal is much higher than that of the LF signal,under the adiabatic approximation condition,the expression of the signal-to-noise ratio (SNR) with respect to the LF signal is obtained.It is shown that the SNR is a non-monotonous function of the amplitude and frequency of the HF signal In addition,the SNR varies non-monotonically with the increasing intensities of the multiplicative and additive noise as well as with the increasing system parameters of the FHN model The influence of the coupling strength between the multiplicative and additive noises on the SNR is discussed.Stochastic resonance (SR) describes the phenomenon where an appropriate amount of noise is of constructive use in the sense that a weak signal becomes amplified upon harvesting the ambient noise in nonlinear systems.[1] Since its first discovery in the early eighties,SR has been observed in a great variety of systems pertaining to different disciplines such as physics,chemistry,engineering,biology and biomedical sciences.[1-4] The phenomenon vibrational resonance (VR) was named by Landa and McClintock.[5]%The vibrational resonance and stochastic resonance phenomena in the FitzHugh-Nagumo (FHN) neural model, driven by a high-frequency (HF) signal and a low-frequency (LF) signal and by coupled multiplicative and additive noises, is investigated. For the case that the frequency of the HF signal is much higher than that of the LF signal, under the adiabatic approximation condition, the expression of the signal-to-noise ratio (SNR) with respect to the LF signal is obtained. It is shown that the SNR is a non-monotonous function of the amplitude and frequency of the HF signal. In addition, the SNR varies non

  9. The Hall module of an exact category with duality

    OpenAIRE

    Young, Matthew B.

    2012-01-01

    We construct from a finitary exact category with duality a module over its Hall algebra, called the Hall module, encoding the first order self-dual extension structure of the category. We study in detail Hall modules arising from the representation theory of a quiver with involution. In this case we show that the Hall module is naturally a module over the specialized reduced sigma-analogue of the quantum Kac-Moody algebra attached to the quiver. For finite type quivers, we explicitly determin...

  10. Dynamic Feedback in Ferromagnet-Spin Hall Metal Heterostructures

    Science.gov (United States)

    Cheng, Ran; Zhu, Jian-Gang; Xiao, Di

    2016-08-01

    In ferromagnet-normal-metal heterostructures, spin pumping and spin-transfer torques are two reciprocal processes that occur concomitantly. Their interplay introduces a dynamic feedback effect interconnecting energy dissipation channels of both magnetization and current. By solving the spin diffusion process in the presence of the spin Hall effect in the normal metal, we show that the dynamic feedback gives rise to (i) a nonlinear magnetic damping that is crucial to sustain uniform steady-state oscillations of a spin Hall oscillator at large angles and (ii) a frequency-dependent spin Hall magnetoimpedance that reduces to the spin Hall magnetoresistance in the dc limit.

  11. Composite particle and field theory in atomic quantum Hall effect

    Institute of Scientific and Technical Information of China (English)

    Zhao Bo; Chen Zeng-Bing

    2005-01-01

    In this paper, we explore the composite particle description of the atomic quantum Hall (QH) effect. We further give the Chern-Simon-Gross-Pitaevskii (CSGP) effective theory for the atomic Hall liquid, which is the counterpart of Chern-Simon theory in electron Hall effect. What we obtained is equivalent to the Laughlin wavefunction approach.Our results show that in terms of composite particles, the atomic Hall effect is really the same as the electronic QH effect. The CSGP effective theory would shed new light on the atomic QH effect.

  12. High Efficiency Hall Thruster Discharge Power Converter Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Busek leveraged previous, internally sponsored, high power, Hall thruster discharge converter development which allowed it to design, build, and test new printed...

  13. Hall Sensor Output Signal Fault-Detection & Safety Implementation Logic

    Directory of Open Access Journals (Sweden)

    Lee SangHun

    2016-01-01

    Full Text Available Recently BLDC motors have been popular in various industrial applications and electric mobility. Recently BLDC motors have been popular in various industrial applications and electric mobility. In most brushless direct current (BLDC motor drives, there are three hall sensors as a position reference. Low resolution hall effect sensor is popularly used to estimate the rotor position because of its good comprehensive performance such as low cost, high reliability and sufficient precision. Various possible faults may happen in a hall effect sensor. This paper presents a fault-tolerant operation method that allows the control of a BLDC motor with one faulty hall sensor and presents the hall sensor output fault-tolerant control strategy. The situations considered are when the output from a hall sensor stays continuously at low or high levels, or a short-time pulse appears on a hall sensor signal. For fault detection, identification of a faulty signal and generating a substitute signal, this method only needs the information from the hall sensors. There are a few research work on hall effect sensor failure of BLDC motor. The conventional fault diagnosis methods are signal analysis, model based analysis and knowledge based analysis. The proposed method is signal based analysis using a compensation signal for reconfiguration and therefore fault diagnosis can be fast. The proposed method is validated to execute the simulation using PSIM.

  14. Probing magnetic microstructures with quasi-ballistic Hall crosses

    Science.gov (United States)

    Fasbender, S.; Schluck, J.; Cerchez, M.; Heinzel, T.; Sievers, S.; Pierz, K.; Schumacher, H. W.

    2016-03-01

    Hall sensing is performed on a localized magnetic field pattern using a quasi-ballistic Hall cross device. The Hall resistance shows a pronounced peak as a function of the magnetic field amplitude which is absent in the magnetization hysteresis loop. This non-monotonic response exemplifies qualitatively the failure of conventional Hall sensing. It is demonstrated how, by using a numerical simulation based on the Landauer-Büttiker model, the amplitude of the magnetic field profile can be determined from such measurements.

  15. Hall and Nernst effects in monolayer MoS2

    Science.gov (United States)

    Zhang, Yun-Hai; Zhang, Ming-Hua

    2016-03-01

    We study Hall and Nernst transports in monolayer MoS2 based on Green’s function formalism. We have derived analytical results for spin and valley Hall conductivities in the zero temperature and spin and valley Nernst conductivities in the low temperature. We found that tuning of the band gap and spin-orbit splitting can drive system transition from spin Hall insulator (SHI) to valley Hall insulator (VHI). When the system is subjected to a temperature gradient, the spin and valley Nernst conductivities are dependent on Berry curvature.

  16. Quantized Anomalous Hall Effect in Magnetic Topological Insulators

    Institute of Scientific and Technical Information of China (English)

    YU Rui

    2011-01-01

    @@ The Hall effect, the anomalous Hall effect (AHE) and the spin Hall effect are fundamental transport processes in solids arising from the Lorentz force and the spin-orbit coupling respectively.The AHE, in which a voltage transverse to the electric current appears even in the absence of an external magnetic field, was first detected in ferromagnetic (FM) metals in 1881 and later found to arise from the spin-orbit coupling (SOC) between the current and magnetic moments.Recent progress on the mechanism of AHE has established a link between the AHE and the topological nature of the Hall current by adopting the Berry-phase concepts in close analogy to the intrinsic spin Hall effect.Given the experimental discovery of the quantum Hall and the quantum spin Hall effects, it is natural to ask whether the AHE can also be quantized.In a quantized anomalous Hall (QAH) insulator, spontaneous magnetic moments and spin-orbit coupling combine to give rise to a topologically non-trivial electronic structure, leading to the quantized Hall effect without any external magnetic field.

  17. MAGNETORESISTANCE AND HALL EFFECT IN SINGLE CRYSTALS OF ALUMINUM

    Science.gov (United States)

    ALUMINUM, *SINGLE CRYSTALS, CRYSTALS, HALL EFFECT , IMPURITIES, LOW PRESSURE, MAGNETIC FIELDS, MAGNETIC PROPERTIES, PARTICLE TRAJECTORIES, ELECTRICAL RESISTANCE, SOLID STATE PHYSICS, SURFACE PROPERTIES.

  18. Laughlin's argument for the quantized thermal Hall effect

    CERN Document Server

    Nakai, Ryota; Nomura, Kentaro

    2016-01-01

    We extend Laughlin's magnetic-flux-threading argument to the quantized thermal Hall effect. A proper analogue of Laughlin's adiabatic magnetic-flux threading process for the case of the thermal Hall effect is given in terms of an external gravitational field. From the perspective of the edge theories of quantum Hall systems, the quantized thermal Hall effect is closely tied to the breakdown of large diffeomorphism invariance, that is, a global gravitational anomaly. In addition, we also give an argument from the bulk perspective in which a free energy, decomposed into its Fourier modes, is adiabatically transferred under an adiabatic process involving external gravitational perturbations.

  19. Beneficios del círculo de abuelos. Policlínica Alex Urquiola. Holguín. 2008-2009

    Directory of Open Access Journals (Sweden)

    Luis Carlos Bruzón-Cabrera

    2012-01-01

    Full Text Available Se realizó un estudio descriptivo para evaluar las ventajas que perciben los ancianos del Policlínico Alex Urquiola con su incorporación a los círculos de abuelos en Holguín en el período 2008- 2009. Se describieron una serie de variables como: la edad, predominando los ancianos de 60 a 74 años, hábitos tóxicos, siendo la ingestión de café el mayoritariamente referido, antecedentes patológicos personales, resultando las patologías osteomioarticulares, Hipertensión Arterial, cardiopatía isquémica y la depresión/ansiedad como las enfermedades más padecidas, el tiempo de permanencia en el círculo de abuelos, fue de 1-5 años y como beneficios de estos refirieron: mejoría en las relaciones interpersonales, de la autoestima y de la calidad del sueño, facilidad de movimientos y disminución del uso de analgésicos y sedantes. Se recomendó incrementar actividades de promoción de salud para su incorporación y permanencia de los ancianos al círculo de abuelos.

  20. Duality in the quantum Hall system

    Science.gov (United States)

    Lütken, C. A.; Ross, G. G.

    1992-05-01

    We suggest that a unified description of the integer and fractional phases of the quantum Hall system may be possible if the scaling diagram of transport coefficients is invariant under linear fractional (modular) transformations. In this model the hierarchy of states, as well as the observed universality of critical exponents, are consequences of a discrete SL(2,openZ) symmetry acting on the parameter space of an effective quantum-field theory. Available scaling data on the position of delocalization fixed points in the integer case and the position of mobility fixed points in the fractional case agree with the model within experimental accuracy.

  1. Twisted CFT and bilayer Quantum Hall systems

    CERN Document Server

    Cristofano, G; Naddeo, A

    2003-01-01

    We identify the impurity interactions of the recently proposed CFT description of a bilayer Quantum Hall system at filling nu =m/(pm+2) in Mod. Phys. Lett. A 15 (2000) 1679. Such a CFT is obtained by m-reduction on the one layer system, with a resulting pairing symmetry and presence of quasi-holes. For the m=2 case boundary terms are shown to describe an impurity interaction which allows for a localized tunnel of the Kondo problem type. The presence of an anomalous fixed point is evidenced at finite coupling which is unstable with respect to unbalance and flows to a vacuum state with no quasi-holes.

  2. Hypernuclear spectroscopy program at JLab Hall C

    Energy Technology Data Exchange (ETDEWEB)

    Hashimoto, Osamu; Hashimoto, Osamu; Nakamura, Satoshi; Acha Quimper, Armando; Ahmidouch, Abdellah; Androic, Darko; Asaturyan, Arshak; Asaturyan, Razmik; Baker, O.; Baturin, Pavlo; Benmokhtar, Fatiha; Bosted, Peter; Carlini, Roger; Chen, X.; Christy, Michael; Cole, Leon; Danagoulian, Samuel; Daniel, AJI; Dharmawardane, Kahanawita; Egiyan, Kim; Elaasar, Mostafa; Ent, Rolf; Fenker, Howard; Fujii, Yu; Furic, Miroslav; Gan, Liping; Gaskell, David; Gasparian, Ashot; Gibson, Edward; Gueye, Paul; Halkyard, Rebekah; Honda, D.; Horn, Tanja; Hu, Bitao; Hu, S.; Hungerford, Ed; Ispiryan, Mikayel; Johnston, Kathleen; Jones, Mark; Kalantarians, Narbe; Kaneta, M.; Kato, F.; Kato, Seigo; Kawama, Daisuke; Keppel, Cynthia; Li, Ya; Luo, Wei; Mack, David; Margaryan, Amur; Marikyan, Gagik; Maruyama, Nayuta; Matsumura, Akihiko; Miyoshi, Toshinobu; Mkrtchyan, Arthur; Mkrtchyan, Hamlet; Navasardyan, Tigran; Niculescu, Gabriel; Niculescu, Maria-Ioana; Nomura, Hiroshi; Nonaka, Kenichi; Ohtani, Atsushi; Okayasu, Yuichi; Pamela, Priscilla; Perez, Naipy; Petkovic, Tomislav; Randeniya, Kapugodage; Reinhold, Joerg; Rivera Castillo, Roberto; Roche, Julie; Rodriguez, Victor; Sato, Yoshinori; Seva, Tomislav; Tang, Liguang; Simicevic, Neven; Smith, Gregory; Sumihama, Mizuki; Song, Y.; Tadevosyan, Vardan; Takahashi, Toshiyuki; Tamura, Hirokazu; Tvaskis, Vladas; Vulcan, William; Wang, B.; Wells, Steven; Yan, Chen; Yuan, Lulin; Zamkochian, S.

    2008-05-01

    DOI: http://dx.doi.org/10.1016/j.nuclphysa.2008.01.029
    Hypernuclear production by the (e,e?K+) reaction has unique advantages in hypernuclear spectroscopy of the S=?1 regime. The second-generation spectroscopy experiment on 12C, 7Li and 28Si targets has been recently carried out at JLab Hall C with a new experimental configuration (Tilt method) and also using a new high-resolution kaon spectrometer (HKS). The experiment is described and preliminary results are presented together with the empasis of significance of the (e,e?K+) reaction for ? hypernuclear spectroscopy and its future prospects.

  3. Current correlations in quantum spin Hall insulators.

    Science.gov (United States)

    Schmidt, Thomas L

    2011-08-26

    We consider a four-terminal setup of a two-dimensional topological insulator (quantum spin Hall insulator) with local tunneling between the upper and lower edges. The edge modes are modeled as helical Luttinger liquids and the electron-electron interactions are taken into account exactly. Using perturbation theory in the tunneling, we derive the cumulant generating function for the interedge current. We show that different possible transport channels give rise to different signatures in the current noise and current cross correlations, which could be exploited in experiments to elucidate the interplay between electron-electron interactions and the helical nature of the edge states.

  4. Anomalous Hall Effect in a Kagome Ferromagnet

    Science.gov (United States)

    Ye, Linda; Wicker, Christina; Suzuki, Takehito; Checkelsky, Joseph; Joseph Checkelsky Team

    The ferromagnetic kagome lattice is theoretically known to possess topological band structures. We have synthesized large single crystals of a kagome ferromagnet Fe3Sn2 which orders ferromagnetically well above room temperature. We have studied the electrical and magnetic properties of these crystals over a broad temperature and magnetic field range. Both the scaling relation of anomalous Hall effect and anisotropic magnetic susceptibility show that the ferromagnetism of Fe3Sn2 is unconventional. We discuss these results in the context of magnetism in kagome systems and relevance to the predicted topological properties in this class of compounds. This research is supported by DMR-1231319.

  5. Supercurrent in the quantum Hall regime

    Science.gov (United States)

    Amet, F.; Ke, C. T.; Borzenets, I. V.; Wang, J.; Watanabe, K.; Taniguchi, T.; Deacon, R. S.; Yamamoto, M.; Bomze, Y.; Tarucha, S.; Finkelstein, G.

    2016-05-01

    A promising route for creating topological states and excitations is to combine superconductivity and the quantum Hall (QH) effect. Despite this potential, signatures of superconductivity in the QH regime remain scarce, and a superconducting current through a QH weak link has been challenging to observe. We demonstrate the existence of a distinct supercurrent mechanism in encapsulated graphene samples contacted by superconducting electrodes, in magnetic fields as high as 2 tesla. The observation of a supercurrent in the QH regime marks an important step in the quest for exotic topological excitations, such as Majorana fermions and parafermions, which may find applications in fault-tolerant quantum computing.

  6. Novel optical probe for quantum Hall system

    Indian Academy of Sciences (India)

    Biswajit Karmakar; Brij Mohan Arora

    2006-07-01

    Surface photovoltage (SPV) spectroscopy has been used for the first time to explore Landau levels of a two-dimensional electron gas (2DEG) in modulation doped InP/InGaAs/InP QW in the quantum Hall regime. The technique gives spectroscopically distinct signals from the bulk Landau levels and the edge states. Evolution of the bulk Landau levels and the edge electronic states is investigated at 2.0 K for magnetic field up to 8 T using SPV spectroscopy.

  7. Excitons in the Fractional Quantum Hall Effect

    Science.gov (United States)

    Laughlin, R. B.

    1984-09-01

    Quasiparticles of charge 1/m in the Fractional Quantum Hall Effect form excitons, which are collective excitations physically similar to the transverse magnetoplasma oscillations of a Wigner crystal. A variational exciton wavefunction which shows explicitly that the magnetic length is effectively longer for quasiparticles than for electrons is proposed. This wavefunction is used to estimate the dispersion relation of these excitons and the matrix elements to generate them optically out of the ground state. These quantities are then used to describe a type of nonlinear conductivity which may occur in these systems when they are relatively clean.

  8. Anesthetic considerations in Sheldon-Hall syndrome.

    Science.gov (United States)

    Anderson, Thomas Anthony; Kasser, James R; Holzman, Robert S

    2014-05-01

    Arthrogryposis is characterized by multiple, nonprogressive joint contractures which may be caused by maternal disorders such as oligohydramnios as well as fetal akinesia resulting from primary disorders of muscle, connective tissue, or neurologic tissue. Its prevalence is about 1 : 3000. Distal arthrogryposis (DA) is a heterogenous group of genetic disorders with a characteristic flexion of the joints of the hands and feet divided into different types with additional features. Sheldon-Hall Syndrome (SHS), also known as distal arthrogryposis type 2A (DA2A), has some nonorthopedic features of specific importance to anesthetic care.

  9. Isolamento e caracterização de Pseudomonas maltophilia (Hugh & Ryschenkow, 1960 de material clínico humano, na cidade do Rio de Janeiro Isolating and characterization of Pseudomonas maltophilia (Hugh & Ryschenkow, 1960 from human clinical specimens, in Rio de Janeiro, Guanabara, Brazil

    Directory of Open Access Journals (Sweden)

    Altair A. Zebral

    1973-01-01

    Full Text Available Os autores estudaram as propriedades morfo-bioquímicas e a sensibilidade às substâncias antimicrobianas, de uma nova e rara espécie de Pseudomonas, a Pseudomonas maltophilia (Hugh & Ryschenkow, 1960, isolada de secração vaginal. Como características marcantes, dentre mais de 65 testadas, as amostras estudadas mostraram ser: oxidase negativa e lisina descarboxilase positiva; produziram desoxiribonuclease e um pigmento escuro que se difunde no meio; atacaram oxidativamente a maltose tanto em meio complexo nitrogenado como em meio de Hugh & Leifson e hidrolisaram a esculina. As amostras foram sensíveis ao cloranfenicol, gentamicina, kanamicina, colistin e gabromicina.The authors have studied the morpho-biochemical properties and the sensibility at antimicrobial drugs, of specie of Pseudomonas, the Pseudomonas maltophilia, (Hugh & Ryschenkow, 1960, isolated from vaginal secretion. Since important characteristics among more of sixty-five tested, the strains studied show to be: oxidase negative and lysine decarboxylase positive; to present deoxyrononuclease activity and produced a diffusible brown pigment: acid was produced by oxidation of maltose as much in nitrogenous complex medium as in Hugh & Leifson medium and they hydrolise the esculin. the strains was sensible, for the colistin chloranfenicol, gabromycin, gentamycin and nalidix acid.

  10. Effect of Joule heating on current-induced asymmetries and breakdown of the quantum Hall effect in narrow Hall bars

    Science.gov (United States)

    Gerhardts, Rolf R.

    2017-01-01

    Recent low-temperature scanning-force-microscopy experiments on narrow Hall bars, under the conditions of the integer quantum Hall effect (IQHE) and its breakdown, have revealed an interesting position dependence of the Hall potential, which changes drastically with the applied magnetic field and the strength of the imposed current through the sample. The present paper shows, that inclusion of Joule heating into an existing self-consistent theory of screening and magneto-transport, which assumes translation invariant Hall bars with a homogeneous background charge due to doping, can explain the experimental results on the breakdown of the IQHE in the so called edge-dominated regime.

  11. Fitz-Hugh-Curtis综合征的腹腔镜诊断及病原菌研究

    Institute of Scientific and Technical Information of China (English)

    姜海燕; 于宏艳; 殷丽华; 姚常晖

    2006-01-01

    Fitz-Hugh-Curtis综合征(FHCS)是盆腔炎合并肝周围炎,诊断需依据直视下观察肝表面和盆腔脏器的炎症表现,和(或)直接从肝表面、盆腔脏器表面检出病原菌,因此受条件限制有许多困难。我们充分利用腹腔镜的探查功能使本病的诊断变得容易。以往报道FHCS病原菌为淋球菌,随着沙眼衣原体感染的急剧增加,本病的报道亦日见增多,由此对其病原菌也提出了质疑。所以本研究拟用腹腔镜协助诊断FHCS及其病原菌,以指导临床诊断与治疗。

  12. Synchronization of coupled different chaotic FitzHugh-Nagumo neurons with unknown parameters under communication-direction-dependent coupling.

    Science.gov (United States)

    Iqbal, Muhammad; Rehan, Muhammad; Khaliq, Abdul; Saeed-ur-Rehman; Hong, Keum-Shik

    2014-01-01

    This paper investigates the chaotic behavior and synchronization of two different coupled chaotic FitzHugh-Nagumo (FHN) neurons with unknown parameters under external electrical stimulation (EES). The coupled FHN neurons of different parameters admit unidirectional and bidirectional gap junctions in the medium between them. Dynamical properties, such as the increase in synchronization error as a consequence of the deviation of neuronal parameters for unlike neurons, the effect of difference in coupling strengths caused by the unidirectional gap junctions, and the impact of large time-delay due to separation of neurons, are studied in exploring the behavior of the coupled system. A novel integral-based nonlinear adaptive control scheme, to cope with the infeasibility of the recovery variable, for synchronization of two coupled delayed chaotic FHN neurons of different and unknown parameters under uncertain EES is derived. Further, to guarantee robust synchronization of different neurons against disturbances, the proposed control methodology is modified to achieve the uniformly ultimately bounded synchronization. The parametric estimation errors can be reduced by selecting suitable control parameters. The effectiveness of the proposed control scheme is illustrated via numerical simulations.

  13. Synchronization of Coupled Different Chaotic FitzHugh-Nagumo Neurons with Unknown Parameters under Communication-Direction-Dependent Coupling

    Directory of Open Access Journals (Sweden)

    Muhammad Iqbal

    2014-01-01

    Full Text Available This paper investigates the chaotic behavior and synchronization of two different coupled chaotic FitzHugh-Nagumo (FHN neurons with unknown parameters under external electrical stimulation (EES. The coupled FHN neurons of different parameters admit unidirectional and bidirectional gap junctions in the medium between them. Dynamical properties, such as the increase in synchronization error as a consequence of the deviation of neuronal parameters for unlike neurons, the effect of difference in coupling strengths caused by the unidirectional gap junctions, and the impact of large time-delay due to separation of neurons, are studied in exploring the behavior of the coupled system. A novel integral-based nonlinear adaptive control scheme, to cope with the infeasibility of the recovery variable, for synchronization of two coupled delayed chaotic FHN neurons of different and unknown parameters under uncertain EES is derived. Further, to guarantee robust synchronization of different neurons against disturbances, the proposed control methodology is modified to achieve the uniformly ultimately bounded synchronization. The parametric estimation errors can be reduced by selecting suitable control parameters. The effectiveness of the proposed control scheme is illustrated via numerical simulations.

  14. Effect of spatially correlated noise on stochastic synchronization in globally coupled FitzHugh-Nagumo neuron systems

    Directory of Open Access Journals (Sweden)

    Yange Shao

    2014-01-01

    Full Text Available The phenomenon of stochastic synchronization in globally coupled FitzHugh-Nagumo (FHN neuron system subjected to spatially correlated Gaussian noise is investigated based on dynamical mean-field approximation (DMA and direct simulation (DS. Results from DMA are in good quantitative or qualitative agreement with those from DS for weak noise intensity and larger system size. Whether the consisting single FHN neuron is staying at the resting state, subthreshold oscillatory regime, or the spiking state, our investigation shows that the synchronization ratio of the globally coupled system becomes higher as the noise correlation coefficient increases, and thus we conclude that spatial correlation has an active effect on stochastic synchronization, and the neurons can achieve complete synchronization in the sense of statistics when the noise correlation coefficient tends to one. Our investigation also discloses that the noise spatial correlation plays the same beneficial role as the global coupling strength in enhancing stochastic synchronization in the ensemble. The result might be useful in understanding the information coding mechanism in neural systems.

  15. Pulse propagation and failure in the discrete FitzHugh-Nagumo model subject to high-frequency stimulation.

    Science.gov (United States)

    Ratas, Irmantas; Pyragas, Kestutis

    2012-10-01

    We investigate the effect of a homogeneous high-frequency stimulation (HFS) on a one-dimensional chain of coupled excitable elements governed by the FitzHugh-Nagumo equations. We eliminate the high-frequency term by the method of averaging and show that the averaged dynamics depends on the parameter A=a/ω equal to the ratio of the amplitude a to the frequency ω of the stimulating signal, so that for large frequencies an appreciable effect from the HFS is attained only at sufficiently large amplitudes. The averaged equations are analyzed by an asymptotic theory based on the different time scales of the recovery and excitable variables. As a result, we obtain the main characteristics of a propagating pulse as functions of the parameter A and derive an analytical criterion for the propagation failure. We show that depending on the parameter A, the HFS can either enhance or suppress pulse propagation and reveal the mechanism underlying these effects. The theoretical results are confirmed by numerical simulations of the original system with and without noise.

  16. Intrinsic valley Hall effect in graphene

    Science.gov (United States)

    Yang, Mou; Zhang, Wen-Lian; Liu, Hai; Bai, Yan-Kui

    2017-04-01

    If electrons are incident from an armchair graphene ribbon into the bulk graphene region, the electronic diffraction occurs. Because of the different triangular wrapping of the energy dispersion between valleys K and K ‧ , the electrons of valley K tend to be diffracted to one side and those of valley K ‧ to the other side. When the current is injected from the armchair ribbon of a four-terminal graphene device, the major portion of the incident current of valley K flows through one side arm and the minor portion through the other side arm. The ratio between them is derived to be 1 + 4 E / 3 in the low energy limit, where E is the energy in units of hopping parameter. The major arm for valley K is the minor arm for valley K ‧ . This results in the rise of the valley Hall effect, which is an intrinsic property of graphene stemming from the different electronic structure of the two valleys. The valley Hall conductance is calculated to be (2 E / 3)G0 with G0 being the conductance supported by the injection ribbon.

  17. Repurposing the Caltech Robinson Hall Coelostat

    Science.gov (United States)

    Treffers, Richard R.; Loisos, G.; Ubbelohde, M.; Douglas, S.; Martinez, M.

    2013-01-01

    We describe the repurposing of the historic coelostat atop Caltech’s Robinson Hall for building lighting, public education and scientific research. The coelostat was originally part of George Ellery Hale’s vision of the Astrophysical Laboratory on the Caltech campus in 1932. The coelostat, designed by Russell Porter, has a 36 inch diameter primary mirror a 30 inch diameter secondary mirror and provides a 24 inch un-vignetted beam of sunlight into the building. Although constructed in the 1930s, due to wartime pressures and other projects, it was used only briefly in the 1970s and never fully realized. Recently Robinson Hall has been fully renovated to house the Ronald and Maxine Linde Center for Global Environmental Science. The coelostat operation was modernized replacing the old motors and automating all the motions. Each morning, if the weather cooperates, the dome slit opens, the mirrors configured and sunlight pours into the building. The beam of sunlight is divided into three parts. One part goes into a refracting telescope which projects a ten inch diameter of the sun onto a ground glass screen visible to the public. A second fraction is distributed to fiber optic fixtures that illuminate some of the basement rooms. The final fraction goes into two laboratories where it is used in experiments monitoring trace constituents of our atmosphere and for solar catalysis experiments. The instrument as originally conceived required at least two human operators. Now it is fully automatic and doing real science

  18. Plume Comparisons between Segmented Channel Hall Thrusters

    Science.gov (United States)

    Niemack, Michael; Staack, David; Raitses, Yevgeny; Fisch, Nathaniel

    2001-10-01

    Angular ion flux plume measurements were taken in several configurations of segmented channel Hall thrusters. The configurations differed by the placement of relatively short rings made from materials with different conductive and secondary electron emission properties along the boron nitride ceramic channel of the thrusters (these have been shown to affect the plume [1]). The ion fluxes are compared with ion trajectory simulations based on plasma potential data acquired with a high speed emissive probe [2]. Preliminary results indicate that in addition to the physical properties of the segments, the plume angle can be strongly affected by the placement of segmented rings relative to the external and internal walls of the channel. [1] Y. Raitses, L. Dorf, A. Litvak and N. J. Fisch, Journal of Applied Physics 88, 1263, 2000 [2] D. Staack, Y. Raitses, N. J. Fisch, Parametric Investigations of Langmuir Probe Induced Perturbations in a Hall Thruster, DPP01 Poster Presentation This work was supported by the U.S. DOE Contract No. DE-ACO2-76-CHO3073.

  19. Radiation heating in sports halls. Stralingsverwarming in sporthallen

    Energy Technology Data Exchange (ETDEWEB)

    Blokpoel, L.

    1994-03-01

    The aim of the study on the title subject was to determine whether by means of the application of radiation heating the required level of thermal comfort in sporting halls can be realized and how much energy is needed to realize such comfort. In two sporting halls the air heating installation was replaced by a radiant heating system. In the sports hall 'D'n Treffer' in Maasbree, Netherlands, infrared radiators were installed, and in the sports hall 'de Taxandriahal' in Waalwijk, Netherlands, so-called dark radiators were installed. After a brief introduction on how to define and quantify thermal comfort, measured results for both sporting halls are presented and discussed. Also the results of a survey among the users of the sporting halls to determine their opinion on the thermal comfort in the halls are presented. The survey was carried out by the authority that commissioned this study, The Dutch National Sports Federation (NSF). In general it can be concluded that radiation heating is a well applicable heating system for sports halls. 17 figs., 8 ills., 10 tabs., 8 appendices

  20. A Larger Scale. Tenth Annual Residence Hall Construction Report.

    Science.gov (United States)

    Argon, Joe

    1999-01-01

    Presents data from the American School & University's 10th Annual Residence Hall Construction Report that show dormitories are costing more per square foot to build while also becoming larger accommodations. Data tables are provided as are highlighted discussions that include residence hall design flexibility, environmental concerns and building…

  1. The first vineyard concert hall in North America

    Science.gov (United States)

    Jaffe, Christopher; Rivera, Carlos

    2002-11-01

    The first vineyard or surround concert hall designed and built in the Western Hemisphere is the Sala Nezahualcoyotl in Mexico City. The Hall was completed in 1976 and is part of the Cultural Center at the Universidad Nacional Autonoma de Mexico. The hall was named after a Toltec poet, architect, and musician who lived in the 15th century and was the Renaissance man of his day. In order to provide the familiar traditional sound of the rectangular (shoebox) European Hall, the acoustic designers set the criteria for reverberation times through the frequency spectrum and the Initial Time Delay Gap at every seat in the house to match the measurements taken at the Grosser Musik vereinssaal in Vienna and Boston Symphony Hall. In this paper we discuss the techniques used to create the traditional sound in a vineyard hall and the reaction of musicians and audiences to the completed facility. The Sala was the model for Suntory Hall in Japan which in turn spawned a number of vineyard halls in Japan. Most recently, the vineyard style seems to be appealing to more and more symphonic organizations in Europe and North America.

  2. Stuart Hall on Racism and the Importance of Diasporic Thinking

    Science.gov (United States)

    Rizvi, Fazal

    2015-01-01

    In this article, I want to show how my initial encounter with the work of Stuart Hall was grounded in my reading of the later philosophy of Ludwig Wittgenstein, and was shaped by my interest in understanding the nature of racism across the three countries in which I had lived. Over the years, Hall's various writings have helped me to make sense of…

  3. Acoustic investigations of concert halls for rock music

    DEFF Research Database (Denmark)

    Adelman-Larsen, Niels Werner; Thompson, Eric Robert; Gade, Anders Christian

    2007-01-01

    Objective measurement data and subjective evaluations have been collected from 20 small-/medium-sized halls in Denmark used for amplified rhythmic music concerts (pop, rock, jazz). The purpose of the study was to obtain knowledge about optimum acoustic conditions for this type of hall. The study...

  4. Cultural Composition: Stuart Hall on Ethnicity and the Discursive Turn.

    Science.gov (United States)

    Drew, Julie

    1998-01-01

    Interviews Stuart Hall, a black public intellectual and an activist of the New Left. Discusses the growing disillusionment with cultural studies now that it is no longer in its ascendancy; the proliferation of pedagogical practices given a cultural studies tag; Hall's approval of the use of popular culture in the composition classroom; and the…

  5. Stuart Hall on Racism and the Importance of Diasporic Thinking

    Science.gov (United States)

    Rizvi, Fazal

    2015-01-01

    In this article, I want to show how my initial encounter with the work of Stuart Hall was grounded in my reading of the later philosophy of Ludwig Wittgenstein, and was shaped by my interest in understanding the nature of racism across the three countries in which I had lived. Over the years, Hall's various writings have helped me to make sense of…

  6. Pair spectrometer hodoscope for Hall D at Jefferson Lab

    Energy Technology Data Exchange (ETDEWEB)

    Barbosa, F.; Hutton, C.; Sitnikov, A. [Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (United States); Somov, A., E-mail: somov@jlab.org [Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (United States); Somov, S.; Tolstukhin, I. [National Research Nuclear University MEPhI, Moscow (Russian Federation)

    2015-09-21

    We present the design of the pair spectrometer hodoscope fabricated at Jefferson Lab and installed in the experimental Hall D. The hodoscope consists of thin scintillator tiles; the light from each tile is collected using wave-length shifting fibers and detected using a Hamamatsu silicon photomultiplier. Light collection was measured using relativistic electrons produced in the tagger area of the experimental Hall B.

  7. Mary E. Hall: Dawn of the Professional School Librarian

    Science.gov (United States)

    Alto, Teresa

    2012-01-01

    A century ago, a woman named Mary E. Hall convinced school leaders of the need for the professional school librarian--a librarian who cultivated a love of reading, academic achievement, and independent learning skills. After graduating from New York City's Pratt Institute Library School in 1895, Hall developed her vision for the high school…

  8. Varsity Hall: The Infirmary at the University of Virginia

    Science.gov (United States)

    Christmas, William A.; Turner, James C.

    2008-01-01

    In the past 5 years, an important treasure for the field of college health was rediscovered and has been completely renovated. It is the original student infirmary, now called Varsity Hall, at the University of Virginia in Charlottesville. Varsity Hall is a significant rediscovery for those who are interested in the history of college health. This…

  9. Useful Pedagogical Applications of the Classical Hall Effect

    Science.gov (United States)

    Houari, Ahmed

    2007-01-01

    One of the most known phenomena in physics is the Hall effect. This is mainly due to its simplicity and to the wide range of its theoretical and practical applications. To complete the pedagogical utility of the Hall effect in physics teaching, I will apply it here to determine the Faraday constant as a fundamental physical number and the number…

  10. Spatial sensitivity mapping of Hall crosses using patterned magnetic nanostructures

    NARCIS (Netherlands)

    Alexandrou, M.; Nutter, P.W.; Delalande, M.Y.; Vries, de J.; Hill, E.W.; Schedin, F.; Abelmann, L.; Thomson, T.

    2010-01-01

    Obtaining an accurate profile of the spatial sensitivity of Hall cross structures is crucial if such devices are to be used to analyze the switching behavior of magnetic nanostructures and determine the switching field distribution of bit patterned media. Here, we have used the anomalous Hall effect

  11. Bulk Versus Edge in the Quantum Hall Effect

    OpenAIRE

    Kao, Y. -C.; Lee, D.-H.

    1996-01-01

    The manifestation of the bulk quantum Hall effect on edge is the chiral anomaly. The chiral anomaly {\\it is} the underlying principle of the ``edge approach'' of quantum Hall effect. In that approach, $\\sxy$ should not be taken as the conductance derived from the space-local current-current correlation function of the pure one-dimensional edge problem.

  12. Efecto Hall del In en Película Evaporada

    OpenAIRE

    Herrera de Camboa, María Elena

    2015-01-01

    El efecto Hall demostrado por Edwin Herbert Hall (1) en 1879 ha venido a ser un hecho importante para la comprension del coruportamiento de los portadores de carga en la conduccion electrica. Es por esto que es necesario investigar este fenomeno en Ia Física del Estado Solido en los diferentes solidos.

  13. Fractional quantum Hall states of bosons on cones

    Science.gov (United States)

    Wu, Ying-Hai; Tu, Hong-Hao; Sreejith, G. J.

    2017-09-01

    Motivated by a recent experiment, which synthesizes Landau levels for photons on cones [Schine et al., Nature (London) 534, 671 (2016), 10.1038/nature17943], and more generally the interest in understanding gravitational responses of quantum Hall states, we study fractional quantum Hall states of bosons on cones. A variety of trial wave functions for conical systems are constructed and compared with exact diagonalization results. The tip of a cone is a localized geometrical defect with singular curvature, which can modify the density profiles of quantum Hall states. The density profiles on cones can be used to extract some universal information about quantum Hall states. The values of certain quantities are computed numerically using the density profiles of some quantum Hall states and they agree with analytical predictions.

  14. Construction and Operation of a Differential Hall Element Magnetometer

    Science.gov (United States)

    Calkins, Matthew W.; Javernick, Philip D.; Quintero, Pedro A.; Calm, Yitzi M.; Meisel, Mark W.

    2012-02-01

    A Differential Hall Element Magnetometer (DHEM) was constructed to measure the magnetic saturation and coercive fields of small samples consisting of magnetic nanoparticles that may have biomedical applications. The device consists of two matched Hall elements that can be moved through the room temperature bore of a 9 Tesla superconducting magnet. The Hall elements are wired in opposition such that a null response, to within a small offset, is measured in the absence of a sample that may be located on top of one unit. A LabVIEW program controls the current through the Hall elements and measures the net Hall voltage while simultaneously moving the probe through the magnetic field by regulating a linear stepper motor. Ultimately, the system will be tested to obtain a figure of merit using successively smaller samples. Details of the apparatus will be provided along with preliminary data.

  15. Topological insulator in junction with ferromagnets: Quantum Hall effects

    Science.gov (United States)

    Chudnovskiy, A. L.; Kagalovsky, V.

    2015-06-01

    The ferromagnet-topological insulator-ferromagnet (FM-TI-FM) junction exhibits thermal and electrical quantum Hall effects. The generated Hall voltage and transverse temperature gradient can be controlled by the directions of magnetizations in the FM leads, which inspires the use of FM-TI-FM junctions as electrical and as heat switches in spintronic devices. Thermal and electrical Hall coefficients are calculated as functions of the magnetization directions in ferromagnets and the spin-relaxation time in TI. Both the Hall voltage and the transverse temperature gradient decrease but are not completely suppressed even at very short spin-relaxation times. The Hall coefficients turn out to be independent of the spin-relaxation time for symmetric configuration of FM leads.

  16. Quantum Hall effect in kagome lattices under staggered magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Zhiyong, E-mail: zyzhang@nju.edu.cn [Department of Physics, Nanjing University, Nanjing 210093 (China)

    2011-10-26

    The interplay of staggered magnetic field (SMF) and uniform magnetic field (UMF) on the quantum Hall effect (QHE) in kagome lattices is investigated in the weak UMF limit. The topological band gaps coming from SMF are robust against UMF although the extended bands split into a series of Landau levels. With SMF applied, in the unconventional QHE region, one plateau of Hall conductance becomes wider and the others are compressed. Meanwhile, one of the two series of integer Hall plateaus splits and the resulting two series of Hall plateaus still exhibit the integer behavior. The Hall conductance varies with SMF step by step with the step height being e{sup 2}/h or 2e{sup 2}/h according to the QHE being conventional or unconventional. In the transitional regions, redistribution of Chern numbers happens even in the weak UMF limit. (paper)

  17. Unconventional quantum Hall effect in Floquet topological insulators

    KAUST Repository

    Tahir, M.

    2016-07-27

    We study an unconventional quantum Hall effect for the surface states of ultrathin Floquet topological insulators in a perpendicular magnetic field. The resulting band structure is modified by photon dressing and the topological property is governed by the low-energy dynamics of a single surface. An exchange of symmetric and antisymmetric surface states occurs by reversing the lights polarization. We find a novel quantum Hall state in which the zeroth Landau level undergoes a phase transition from a trivial insulator state, with Hall conductivity αyx = 0 at zero Fermi energy, to a Hall insulator state with αyx = e2/2h. These findings open new possibilities for experimentally realizing nontrivial quantum states and unusual quantum Hall plateaus at (±1/2,±3/2,±5/2, ...)e2/h. © 2016 IOP Publishing Ltd Printed in the UK.

  18. Axisymmetric Nonlinear Waves And Structures in Hall Plasmas

    CERN Document Server

    Islam, Tanim

    2011-01-01

    A Hall plasma consists of a plasma with not all species frozen into the magnetic field. In this paper, a general equation for the evolution of an axisymmetric magnetic field in a Hall plasma is derived, with an integral similar to the Grad-Shafranov equation. Special solutions arising from curvature -- whistler drift modes that propagate along the electron drift as a Burger's shock, and nonlinear periodic and soliton-like solutions to the generalized Grad-Shafranov integral -- are analyzed. We derive analytical and numerical solutions in an electron-ion Hall plasma, in which electrons and ions are the only species in the plasmas. Results may then be applied to electron-ion-gas Hall plasmas, in which the ions are coupled to the motion of gases in low ionized plasmas (lower ionosphere and protostellar disks), and to dusty Hall plasmas (such as molecular clouds), in which the much heavier charged dust may be collisionally coupled to the gas.

  19. Experimental evidence for a two-dimensional quantized Hall insulator

    Science.gov (United States)

    Hilke, M.; Shahar, D.; Song, S. H.; Tsui, D. C.; Xie, Y. H.; Monroe, Don

    1998-10-01

    The general theoretical definition of an insulator is a material in which the conductivity vanishes at the absolute zero of temperature. In classical insulators, such as materials with a band gap, vanishing conductivities lead to diverging resistivities. But other insulators can show more complex behaviour, particularly in the presence of a high magnetic field, where different components of the resistivity tensor can display different behaviours: the magnetoresistance diverges as the temperature approaches absolute zero, but the transverse (Hall) resistance remains finite. Such a system is known as a Hall insulator. Here we report experimental evidence for a quantized Hall insulator in a two-dimensional electron system-confined in a semiconductor quantum well. The Hall resistance is quantized in the quantum unit of resistance h/e2, where h is Planck's constant and e the electronic charge. At low fields, the sample reverts to being a normal Hall insulator.

  20. Geometric spin Hall effect of light with inhomogeneous polarization

    Science.gov (United States)

    Ling, Xiaohui; Zhou, Xinxing; Yi, Xunong

    2017-01-01

    The spin Hall effect of light originates from spin-orbit interaction of light, which manifests two types of geometric phases. In this paper, we report the observation of a geometric spin Hall effect by generating a light beam with inhomogeneous polarization distribution. Unlike the previously reported geometric spin Hall effect observed in a tilted beam-detector system, which is believed to result from an effective spin-redirection Berry geometric phase, the geometric spin Hall effect demonstrated here is attributed to an effective, spatially varying Pancharatnam-Berry geometric phase generated by the inhomogeneous polarization geometry. Our further experiments show that the geometric spin Hall effect can be tuned by tailoring the polarization geometry of light, demonstrating the spin states of photons can be steered with a great flexibility.

  1. In-plane magnetization-induced quantum anomalous Hall effect.

    Science.gov (United States)

    Liu, Xin; Hsu, Hsiu-Chuan; Liu, Chao-Xing

    2013-08-23

    The quantum Hall effect can only be induced by an out-of-plane magnetic field for two-dimensional electron gases, and similarly, the quantum anomalous Hall effect has also usually been considered for systems with only out-of-plane magnetization. In the present work, we predict that the quantum anomalous Hall effect can be induced by in-plane magnetization that is not accompanied by any out-of-plane magnetic field. Two realistic two-dimensional systems, Bi2Te3 thin film with magnetic doping and HgMnTe quantum wells with shear strains, are presented and the general condition for the in-plane magnetization-induced quantum anomalous Hall effect is discussed based on the symmetry analysis. Nonetheless, an experimental setup is proposed to confirm this effect, the observation of which will pave the way to search for the quantum anomalous Hall effect in a wider range of materials.

  2. Unconventional quantum Hall effect in Floquet topological insulators.

    Science.gov (United States)

    Tahir, M; Vasilopoulos, P; Schwingenschlögl, U

    2016-09-28

    We study an unconventional quantum Hall effect for the surface states of ultrathin Floquet topological insulators in a perpendicular magnetic field. The resulting band structure is modified by photon dressing and the topological property is governed by the low-energy dynamics of a single surface. An exchange of symmetric and antisymmetric surface states occurs by reversing the light's polarization. We find a novel quantum Hall state in which the zeroth Landau level undergoes a phase transition from a trivial insulator state, with Hall conductivity [Formula: see text] at zero Fermi energy, to a Hall insulator state with [Formula: see text]. These findings open new possibilities for experimentally realizing nontrivial quantum states and unusual quantum Hall plateaus at [Formula: see text].

  3. Formulation of the Relativistic Quantum Hall Effect and "Parity Anomaly"

    CERN Document Server

    Yonaga, Kouki; Shibata, Naokazu

    2016-01-01

    We present a relativistic formulation of the quantum Hall effect on a Riemann sphere. An explicit form of the pseudopotential is derived for the relativistic quantum Hall effect with/without mass term.We clarify particular features of the relativistic quantum Hall states with use of the exact diagonalization study of the pseudopotential Hamiltonian. Physical effects of the mass term to relativistic quantum Hall states are investigated in detail.The mass term acts as an interporating parameter between the relativistic and non-relativistic quantum Hall effects. It is pointed out that the mass term inequivalently affects to many-body physics of the positive and negative Landau levels and brings instability of the Laughlin state of the positive first relativistic Landau level as a consequence of the "parity anomaly".

  4. [University residence halls: socialization processes and drug consumption].

    Science.gov (United States)

    Laranjo, Thais Helena Mourão; Soares, Cássia Baldini

    2006-12-01

    To investigate and analyze the discourse of students living in university residence halls regarding socialization processes and drug consumption. This was qualitative research among 20 undergraduate students living in university residence halls in the city of São Paulo, Brazil, in 2003. Residence halls were taken to be socialization spaces for young people that enable the presence of low-income students at university. The interviews covered students' knowledge of the history of the residence hall, their experience of living in student residences and their perceptions regarding drug consumption. The methodological procedure that served as the basis for collection, organization and analysis of the interview data was examination of the collective discourse of the subjects. It was shown that the students had little knowledge of the history of the residence hall; solutions for problems they faced in the residence hall were sought individually; and the two main concepts observed among the people living there for preventing drug consumption were war on drugs and damage limitation. It was seen that there was a negative view regarding student residence halls that related to the constant publication of disturbing events and lack of knowledge of the importance of residence halls for enabling poor students to remain at university. In the opinion of the people living in student residence halls, such accommodation enables access to university, despite the difficulties in living together and in administration by the university. With regard to the use of drugs in the residence hall, some of the people living there emphasized the need for less tolerance towards drug consumption, while others stressed the importance of educational work, particularly among those who are just starting to live there.

  5. Hypolipidemic and Antioxidant Effects of Malus toringoides (Rehd.) Hughes Leaves in High-Fat-Diet-Induced Hyperlipidemic Rats.

    Science.gov (United States)

    Huang, Shan; Liu, Haifeng; Meng, Ning; Li, Bin; Wang, Jule

    2017-03-01

    Malus toringoides (Rehd.) Hughes (MT) leaves are traditionally used as a medicine for treating or preventing cardiovascular disease in Tibet. In addition to the effect of this medicinal plant on thrombosis, we tested its effect on dyslipidemia in a hypolipidemic rat model. A total of 60 healthy Sprague-Dawley rats were randomly divided into six groups, as follows: normal control, model control, simvastatin groups, and MT low-, medium-, and high-dose groups. The normal controls were fed with a normal diet, whereas all other groups were fed with a high-fat diet. After 6 weeks, the high-fat diet had induced hyperlipidemia in the rats, which were then orally administered with different doses of MT leaf extract (50, 100, and 200 mg/kg) for an additional 6 weeks. Serum levels of total cholesterol (TC), triglycerides (TG), low- and high-density lipoprotein cholesterol (LDL-c and HDL-c, respectively), as well as the antioxidant capacity of glutathione peroxidase (GSHP-x), superoxide dismutase (SOD), and malondialdehyde (MDA) were measured at the end of the study. MT significantly reduced serum TC, TG, and LDL-c and increased the HDL-c content in MT-treated rats compared with the model group. These changes were dose dependent. MT treatment also significantly elevated the activity of SOD and GSHP-x, and decreased the serum levels of MDA compared with untreated hyperlipidemic rats, thereby increasing serum antioxidant capacity. In addition, MT reduced liver steatosis in hyperlipidemic rats. Overall, MT exerts considerable hypolipidemic and antioxidant properties.

  6. Mean-field description and propagation of chaos in networks of Hodgkin-Huxley and FitzHugh-Nagumo neurons.

    Science.gov (United States)

    Baladron, Javier; Fasoli, Diego; Faugeras, Olivier; Touboul, Jonathan

    2012-05-31

    We derive the mean-field equations arising as the limit of a network of interacting spiking neurons, as the number of neurons goes to infinity. The neurons belong to a fixed number of populations and are represented either by the Hodgkin-Huxley model or by one of its simplified version, the FitzHugh-Nagumo model. The synapses between neurons are either electrical or chemical. The network is assumed to be fully connected. The maximum conductances vary randomly. Under the condition that all neurons' initial conditions are drawn independently from the same law that depends only on the population they belong to, we prove that a propagation of chaos phenomenon takes place, namely that in the mean-field limit, any finite number of neurons become independent and, within each population, have the same probability distribution. This probability distribution is a solution of a set of implicit equations, either nonlinear stochastic differential equations resembling the McKean-Vlasov equations or non-local partial differential equations resembling the McKean-Vlasov-Fokker-Planck equations. We prove the well-posedness of the McKean-Vlasov equations, i.e. the existence and uniqueness of a solution. We also show the results of some numerical experiments that indicate that the mean-field equations are a good representation of the mean activity of a finite size network, even for modest sizes. These experiments also indicate that the McKean-Vlasov-Fokker-Planck equations may be a good way to understand the mean-field dynamics through, e.g. a bifurcation analysis.Mathematics Subject Classification (2000): 60F99, 60B10, 92B20, 82C32, 82C80, 35Q80.

  7. Geometric Photonic Spin Hall Effect with Metapolarization

    CERN Document Server

    Ling, Xiaohui; Yi, Xunong; Luo, Hailu; Wen, Shuangchun

    2014-01-01

    We develop a geometric photonic spin Hall effect (PSHE) which manifests as spin-dependent shift in momentum space. It originates from an effective space-variant Pancharatnam-Berry (PB) phase created by artificially engineering the polarization distribution of the incident light. Unlikely the previously reported PSHE involving the light-matter interaction, the resulting spin-dependent splitting in the geometric PSHE is purely geometrically depend upon the polarization distribution of light which can be tailored by assembling its circular polarization basis with suitably magnitude and phase. This metapolarization idea enables us to manipulate the geometric PSHE by suitably tailoring the polarization geometry of light. Our scheme provides great flexibility in the design of various polarization geometry and polarization-dependent application, and can be extrapolated to other physical system, such as electron beam or atom beam, with the similar spin-orbit coupling underlying.

  8. Photonic analogue of quantum spin Hall effect

    CERN Document Server

    He, Cheng; Liu, Xiao-ping; Lu, Ming-Hui; Chen, Yulin; Feng, Liang; Chen, Yan-Feng

    2014-01-01

    Symmetry-protected photonic topological insulator exhibiting robust pseudo-spin-dependent transportation, analogous to quantum spin Hall (QSH) phases and topological insulators, are of great importance in fundamental physics. Such transportation robustness is protected by time-reversal symmetry. Since electrons (fermion) and photons (boson) obey different statistics rules and associate with different time-reversal operators (i.e., Tf and Tb, respectively), whether photonic counterpart of Kramers degeneracy is topologically protected by bosonic Tb remains unidentified. Here, we construct the degenerate gapless edge states of two photonic pseudo-spins (left/right circular polarizations) in the band gap of a two-dimensional photonic crystal with strong magneto-electric coupling. We further demonstrated that the topological edge states are in fact protected by Tf rather than commonly believed Tb and their pseudo-spin dependent transportation is robust against Tf invariant impurities, discovering for the first tim...

  9. Gauge Physics of Spin Hall Effect

    Science.gov (United States)

    Tan, Seng Ghee; Jalil, Mansoor B. A.; Ho, Cong Son; Siu, Zhuobin; Murakami, Shuichi

    2015-12-01

    Spin Hall effect (SHE) has been discussed in the context of Kubo formulation, geometric physics, spin orbit force, and numerous semi-classical treatments. It can be confusing if the different pictures have partial or overlapping claims of contribution to the SHE. In this article, we present a gauge-theoretic, time-momentum elucidation, which provides a general SHE equation of motion, that unifies under one theoretical framework, all contributions of SHE conductivity due to the kinetic, the spin orbit force (Yang-Mills), and the geometric (Murakami-Fujita) effects. Our work puts right an ambiguity surrounding previously partial treatments involving the Kubo, semiclassical, Berry curvatures, or the spin orbit force. Our full treatment shows the Rashba 2DEG SHE conductivity to be instead of -, and Rashba heavy hole instead of -. This renewed treatment suggests a need to re-derive and re-calculate previously studied SHE conductivity.

  10. On-Chip Microwave Quantum Hall Circulator

    Science.gov (United States)

    Mahoney, A. C.; Colless, J. I.; Pauka, S. J.; Hornibrook, J. M.; Watson, J. D.; Gardner, G. C.; Manfra, M. J.; Doherty, A. C.; Reilly, D. J.

    2017-01-01

    Circulators are nonreciprocal circuit elements that are integral to technologies including radar systems, microwave communication transceivers, and the readout of quantum information devices. Their nonreciprocity arises from the interference of microwaves over the centimeter scale of the signal wavelength, in the presence of bulky magnetic media that breaks time-reversal symmetry. Here, we realize a completely passive on-chip microwave circulator with size 1 /1000 th the wavelength by exploiting the chiral, "slow-light" response of a two-dimensional electron gas in the quantum Hall regime. For an integrated GaAs device with 330 μ m diameter and about 1-GHz center frequency, a nonreciprocity of 25 dB is observed over a 50-MHz bandwidth. Furthermore, the nonreciprocity can be dynamically tuned by varying the voltage at the port, an aspect that may enable reconfigurable passive routing of microwave signals on chip.

  11. Photonic spin Hall effect in topological insulators

    CERN Document Server

    Zhou, Xinxing; Ling, Xiaohui; Chen, Shizhen; Luo, Hailu; Wen, Shuangchun

    2013-01-01

    In this paper we theoretically investigate the photonic spin Hall effect (SHE) of a Gaussian beam reflected from the interface between air and topological insulators (TIs). The photonic SHE is attributed to spin-orbit coupling and manifests itself as in-plane and transverse spin-dependent splitting. We reveal that the spin-orbit coupling effect in TIs can be routed by adjusting the axion angle variations. Unlike the transverse spin-dependent splitting, we find that the in-plane one is sensitive to the axion angle. It is shown that the polarization structure in magneto-optical Kerr effect is significantly altered due to the spin-dependent splitting in photonic SHE. We theoretically propose a weak measurement method to determine the strength of axion coupling by probing the in-plane splitting of photonic SHE.

  12. Hydrodynamic Electron Flow and Hall Viscosity

    Science.gov (United States)

    Scaffidi, Thomas; Nandi, Nabhanila; Schmidt, Burkhard; Mackenzie, Andrew P.; Moore, Joel E.

    2017-06-01

    In metallic samples of small enough size and sufficiently strong momentum-conserving scattering, the viscosity of the electron gas can become the dominant process governing transport. In this regime, momentum is a long-lived quantity whose evolution is described by an emergent hydrodynamical theory. Furthermore, breaking time-reversal symmetry leads to the appearance of an odd component to the viscosity called the Hall viscosity, which has attracted considerable attention recently due to its quantized nature in gapped systems but still eludes experimental confirmation. Based on microscopic calculations, we discuss how to measure the effects of both the even and odd components of the viscosity using hydrodynamic electronic transport in mesoscopic samples under applied magnetic fields.

  13. Geometric Defects in Quantum Hall States

    CERN Document Server

    Gromov, Andrey

    2016-01-01

    We describe a geometric (or gravitational) analogue of the Laughlin quasiholes in the fractional quantum Hall states. Analogously to the quasiholes these defects can be constructed by an insertion of an appropriate vertex operator into the conformal block representation of a trial wavefunction, however, unlike the quasiholes these defects are extrinsic and do not correspond to true excitations of the quantum fluid. We construct a wavefunction in the presence of such defects and explain how to assign an electric charge and a spin to each defect, and calculate the adiabatic, non-abelian statistics of the defects. The defects turn out to be equivalent to the genons in that their adiabatic exchange statistics can be described in terms of representations of the mapping class group of an appropriate higher genus Riemann surface. We present a general construction that, in principle, allows to calculate the statistics of $\\mathbb Z_n$ genons for any "parent" topological phase. We illustrate the construction on the ex...

  14. Concept of Operating Indoor Skiing Halls with

    DEFF Research Database (Denmark)

    Paul, Joachim

    2003-01-01

    Indoor skiing halls are conventionally operated at low temperatures and with either crushed ice as snow substitute or snow made from freezing water in cold air. Both systems have a high energy demand for air cooling, floor freezing and consequently snow harvest. At the same time the snow at the top...... floor cooling/freezing and insulation become obsolete, significant savings in piping and building costs can be achieved. Due to the much higher evaporating temperature for the refrigeration system, the energy demand is kept low. Since the same equipment is used for both snowmaking and air cooling......, the running time of the equipment is high, resulting in a better economy. Using Binary Snow, with its unique qualities such as fluffy, crisp, white and ¿ since made daily ¿ "fresh and hygienic", offers great advantages in operating costs, investment costs and quality....

  15. Magnetic circuit for hall effect plasma accelerator

    Science.gov (United States)

    Manzella, David H. (Inventor); Jacobson, David T. (Inventor); Jankovsky, Robert S. (Inventor); Hofer, Richard (Inventor); Peterson, Peter (Inventor)

    2009-01-01

    A Hall effect plasma accelerator includes inner and outer electromagnets, circumferentially surrounding the inner electromagnet along a thruster centerline axis and separated therefrom, inner and outer magnetic conductors, in physical connection with their respective inner and outer electromagnets, with the inner magnetic conductor having a mostly circular shape and the outer magnetic conductor having a mostly annular shape, a discharge chamber, located between the inner and outer magnetic conductors, a magnetically conducting back plate, in magnetic contact with the inner and outer magnetic conductors, and a combined anode electrode/gaseous propellant distributor, located at a bottom portion of the discharge chamber. The inner and outer electromagnets, the inner and outer magnetic conductors and the magnetically conducting back plate form a magnetic circuit that produces a magnetic field that is largely axial and radially symmetric with respect to the thruster centerline.

  16. Hall MHD Equilibrium of Accelerated Compact Toroids

    Science.gov (United States)

    Howard, S. J.; Hwang, D. Q.; Horton, R. D.; Evans, R. W.; Brockington, S. J.

    2007-11-01

    We examine the structure and dynamics of the compact toroid's magnetic field. The compact toroid is dramatically accelerated by a large rail-gun Lorentz force density equal to j xB. We use magnetic data from the Compact Toroid Injection Experiment to answer the question of exactly where in the system j xB has nonzero values, and to what extent we can apply the standard model of force-free equilibrium. In particular we present a method of analysis of the magnetic field probe signals that allows direct comparison to the predictions of the Woltjer-Taylor force-free model and Turner's generalization of magnetic relaxation in the presence of a non-zero Hall term and fluid vorticity.

  17. Mesoscopic spin Hall effect in semiconductor nanostructures

    Science.gov (United States)

    Zarbo, Liviu

    The spin Hall effect (SHE) is a name given to a collection of diverse phenomena which share two principal features: (i) longitudinal electric current flowing through a paramagnetic semiconductor or metallic sample leads to transverse spin current and spin accumulation of opposite sign at opposing lateral edges; (ii) SHE does not require externally applied magnetic field or magnetic ordering in the equilibrium state of the sample, instead it relies on the presence of spin-orbit (SO) couplings within the sample. This thesis elaborates on a new type of phenomenon within the SHE family, predicted in our recent studies [Phys. Rev. B 72, 075361 (2005); Phys. Rev. Lett. 95, 046601 (2005); Phys. Rev. B 72, 075335 (2005); Phys. Rev. B 73 , 075303 (2006); and Europhys. Lett. 77, 47004 (2007)], where pure spin current flows through the transverse electrodes attached to a clean finitesize two-dimensional electron gas (2DEG) due to unpolarized charge current injected through its longitudinal leads. If transverse leads are removed, the effect manifests as nonequilibrium spin Hall accumulation at the lateral edges of 2DEG wires. The SO coupling driving this SHE effect is of the Rashba type, which arises due to structural inversion asymmetry of semiconductor heterostructure hosting the 2DEG. We term the effect "mesoscopic" because the spin Hall currents and accumulations reach optimal value in samples of the size of the spin precession length---the distance over which the spin of an electron precesses by an angle pi. In strongly SO-coupled structures this scale is of the order of ˜100 nm, and, therefore, mesoscopic in the sense of being much larger than the characteristic microscopic scales (such as the Fermi wavelength, screening length, or the mean free path in disordered systems), but still much smaller than the macroscopic ones. Although the first theoretical proposal for SHE, driven by asymmetry in SO-dependent scattering of spin-up and spin-down electrons off impurities

  18. Concept of Operating Indoor Skiing Halls with

    DEFF Research Database (Denmark)

    Paul, Joachim

    2003-01-01

    Indoor skiing halls are conventionally operated at low temperatures and with either crushed ice as snow substitute or snow made from freezing water in cold air. Both systems have a high energy demand for air cooling, floor freezing and consequently snow harvest. At the same time the snow at the top...... floor cooling/freezing and insulation become obsolete, significant savings in piping and building costs can be achieved. Due to the much higher evaporating temperature for the refrigeration system, the energy demand is kept low. Since the same equipment is used for both snowmaking and air cooling......, the running time of the equipment is high, resulting in a better economy. Using Binary Snow, with its unique qualities such as fluffy, crisp, white and ¿ since made daily ¿ "fresh and hygienic", offers great advantages in operating costs, investment costs and quality....

  19. The quantum Hall effect and its contexts

    OpenAIRE

    Rodríguez,Víctor

    2017-01-01

    En este artículo, se atienden ciertas facetas conceptuales y experimentales del efecto Hall cuántico. Se argumenta que el mismo ofrece variados matices para la reflexión filosófica, desde la generación de entidades teóricas hasta la epistemología de la experimentación. La exposición pretende mantener cierta sensibilidad por la dinámica histórica en torno del tema, como así también por las implicaciones metrológicas de ámbitos cuánticos específicos. Dada la enorme producción científica sobre e...

  20. Stacking order dependence of inverse spin Hall effect and anomalous Hall effect in spin pumping experiments

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sang-Il; Seo, Min-Su; Park, Seung-Young, E-mail: parksy@kbsi.re.kr [Division of Materials Science, Korea Basic Science Institute, Daejeon 305-806 (Korea, Republic of); Kim, Dong-Jun; Park, Byong-Guk [Department of Materials Science and Engineering, KAIST, Daejeon 305-701 (Korea, Republic of)

    2015-05-07

    The dependence of the measured DC voltage on the non-magnetic material (NM) in NM/CoFeB and CoFeB/NM bilayers is studied under ferromagnetic resonance conditions in a TE{sub 011} resonant cavity. The directional change of the inverse spin Hall effect (ISHE) voltage V{sub ISHE} for the stacking order of the bilayer can separate the pure V{sub ISHE} and the anomalous Hall effect (AHE) voltage V{sub AHE} utilizing the method of addition and subtraction. The Ta and Ti NMs show a broad deviation of the spin Hall angle θ{sub ISH}, which originates from the AHE in accordance with the high resistivity of NMs. However, the Pt and Pd NMs show that the kinds of NMs with low resistivity are consistent with the previously reported θ{sub ISH} values. Therefore, the characteristics that NM should simultaneously satisfy to obtain a reasonable V{sub ISHE} value in bilayer systems are large θ{sub ISH} and low resistivity.

  1. Residencia hall del Obispado, en Gescher, Alemania

    Directory of Open Access Journals (Sweden)

    Deilmann, Harald

    1969-02-01

    Full Text Available This Hall has four lecture rooms, each with a capacity for twenty students. They all face north, have lateral and cenithal illumination and cross ventilation. The workshop training halls face south, and there is a gymnasium. Each classroom is also connected with a protected open air space, so that in suitable weather, teaching can be practised out of doors. As the school is devoted to mentally retarded boys and youths, over 2 m2 of floor area has been allowed for each student in the classrooms, since it was estimated that many students would be of the nervous type and would need more room to work freely. Most of the construction is made with unfaced brick and concrete, which are long lasting materials, requiring little maintenance.Comprende cuatro clases propiamente dichas, con una capacidad total de 80 alumnos, a razón de 20 por cada clase, y orientadas al norte, con iluminación cenital y lateral y ventilación cruzada. Los locales donde se imparten las enseñanzas de taller tienen orientación sur. Se ha previsto, además, un gimnasio. Cada clase dispone de un recinto protegido para que, cuando las condiciones atmosféricas lo permitan, se pueda desarrollar en él la enseñanza al aire libre. Como la escuela está destinada a niños y adolescentes retrasados mentales, se partió de un espacio superior a los 2 m2 por alumno, pensando en que parte de ellos iban a ser niños nerviosos y, como consecuencia, la necesidad que tendrían de amplitud suficiente para desenvolverse adecuadamente. La construcción se ha desarrollado, en general, a base de fábrica de ladrillo a cara vista y hormigón visto, materiales de gran duración y prácticamente exentos de entretenimiento.

  2. Hall transport of divalent metal ion modified DNA lattices

    Energy Technology Data Exchange (ETDEWEB)

    Dugasani, Sreekantha Reddy; Lee, Keun Woo; Yoo, Sanghyun; Gnapareddy, Bramaramba; Bashar, Saima; Park, Sung Ha, E-mail: sunghapark@skku.edu [Department of Physics and Sungkyunkwan Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Kim, Si Joon; Jung, Joohye; Jung, Tae Soo; Kim, Hyun Jae, E-mail: hjk3@yonsei.ac.kr [School of Electrical and Electronic Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of)

    2015-06-29

    We investigate the Hall transport characteristics of double-crossover divalent metal ion (Cu{sup 2+}, Ni{sup 2+}, Zn{sup 2+}, and Co{sup 2+})-modified DNA (M-DNA) lattices grown on silica via substrate-assisted growth. The electronic characteristics of the M-DNA lattices are investigated by varying the concentration of the metal ions and then conducting Hall measurements, including resistivity, Hall mobility, carrier concentration, and magneto resistance. The tendency of the resistivity and Hall mobility was to initially decrease as the ion concentration increased, until reaching the saturation concentration (C{sub s}) of each metal ion, and then to increase as the ion concentration increased further. On the other hand, the carrier concentration revealed the opposite tendency as the resistivity and Hall mobility. The specific binding (≤C{sub s}) and the nonspecific aggregates (>C{sub s}) of the ions into the DNA lattices were significantly affected by the Hall characteristics. The numerical ranges of the Hall parameters revealed that the M-DNA lattices with metal ions had semiconductor-like characteristics. Consequently, the distinct characteristics of the electrical transport through M-DNA lattices will provide useful information on the practical use of such structures in physical devices and chemical sensors.

  3. Effective Field Theory of Fractional Quantized Hall Nematics

    Energy Technology Data Exchange (ETDEWEB)

    Mulligan, Michael; /MIT, LNS; Nayak, Chetan; /Station Q, UCSB; Kachru, Shamit; /Stanford U., Phys. Dept. /SLAC

    2012-06-06

    We present a Landau-Ginzburg theory for a fractional quantized Hall nematic state and the transition to it from an isotropic fractional quantum Hall state. This justifies Lifshitz-Chern-Simons theory - which is shown to be its dual - on a more microscopic basis and enables us to compute a ground state wave function in the symmetry-broken phase. In such a state of matter, the Hall resistance remains quantized while the longitudinal DC resistivity due to thermally-excited quasiparticles is anisotropic. We interpret recent experiments at Landau level filling factor {nu} = 7/3 in terms of our theory.

  4. Audience noise in concert halls during musical performances

    DEFF Research Database (Denmark)

    Marie, Pierre; Jeong, Cheol-Ho; Brunskog, Jonas

    2012-01-01

    Noise generated by the audience during musical performances is audible and sometimes disturbing. In this study, an attempt to estimate such audience noise was carried out. From the recordings of performances in five performance spaces (four concert halls and one opera house), probability density...... prediction models were made using the four orchestra concert halls, revealing that the audience noise level is significantly correlated with the technical background noise level. It is therefore concluded that a relaxation of the current background noise recommendations for concert halls is not recommended....

  5. Audience noise in concert halls during musical performances

    DEFF Research Database (Denmark)

    Jeong, Cheol-Ho; Marie, Pierre; Brunskog, Jonas

    2012-01-01

    Noise generated by the audience during musical performances is audible and sometimes disturbing. In this study, an attempt to estimate such audience noise was carried out. From the recordings of performances in five performance spaces (four concert halls and one opera house), probability density...... prediction models were made using the four orchestra concert halls, revealing that the audience noise level is significantly correlated with the technical background noise level. It is therefore concluded that a relaxation of the current background noise recommendations for concert halls is not recommended...

  6. Anomalous Hall effect in Fe/Gd bilayers

    KAUST Repository

    Xu, W. J.

    2010-04-01

    Non-monotonic dependence of anomalous Hall resistivity on temperature and magnetization, including a sign change, was observed in Fe/Gd bilayers. To understand the intriguing observations, we fabricated the Fe/Gd bilayers and single layers of Fe and Gd simultaneously. The temperature and field dependences of longitudinal resistivity, Hall resistivity and magnetization in these films have also been carefully measured. The analysis of these data reveals that these intriguing features are due to the opposite signs of Hall resistivity/or spin polarization and different Curie temperatures of Fe and Gd single-layer films. Copyright (C) EPLA, 2010

  7. Modelling of micro-Hall sensors for magnetization imaging

    Science.gov (United States)

    Manzin, A.; Nabaei, V.

    2014-05-01

    This paper presents a numerical model for the study of micro-Hall magnetometry applications, aiming at evaluating the sensitivity of semiconductor miniaturized devices to the stray field of permalloy nanostructures with ring and disk geometry. The procedure couples a micromagnetic code, for the calculation of the stray field generated by the nanomagnet, to a 2D classical transport model for the determination of the electric potential distribution inside the Hall plate. The model is applied to study the sensitivity of a micro-Hall device in the detection of magnetization switching processes characterized by vortex state, focusing on the influence of magnetic nanostructure position.

  8. TCC2, the target hall of the SPS North Area

    CERN Multimedia

    1978-01-01

    In the foreground can be seen the three proton beam branches leading to the targets enclosed in an assembly of iron blocks with the positioning mechanism on top. In the background, the six secondary beams lead off towards the experimental areas, H2/P2, H4/E4/P4 (from T2 via TT81) and H6, H8 (from T4 via TT82) towards the hall EHN1, M2 from T6 via TT83 towards the hall EHN2. The development proton beam line P0 leads off from T4 via TT83 towards TCC8 and hall ECN3 (NAHIF).

  9. Composed planar Hall effect sensors with dual-mode operation

    OpenAIRE

    Vladislav Mor; Debangsu Roy; Moty Schultz; Lior Klein

    2016-01-01

    We present a composed planar Hall effect sensor with two modes of operation: (a) an ON mode where the composed sensor responds to magnetic field excitations similarly to the response of a regular planar Hall effect sensor, and (b) an OFF mode where the response is negligible. The composed planar Hall effect sensor switches from the OFF mode to the ON mode when it is exposed to a magnetic field which exceeds a certain threshold determined by the sensor design. The features of this sensor make ...

  10. Hall conductance and topological invariant for open systems.

    Science.gov (United States)

    Shen, H Z; Wang, W; Yi, X X

    2014-09-24

    The Hall conductivity given by the Kubo formula is a linear response of quantum transverse transport to a weak electric field. It has been intensively studied for quantum systems without decoherence, but it is barely explored for systems subject to decoherence. In this paper, we develop a formulism to deal with this issue for topological insulators. The Hall conductance of a topological insulator coupled to an environment is derived, the derivation is based on a linear response theory developed for open systems in this paper. As an application, the Hall conductance of a two-band topological insulator and a two-dimensional lattice is presented and discussed.

  11. Hall effect in CNT doped YBCO high temperature superconductor

    Directory of Open Access Journals (Sweden)

    S Dadras

    2010-09-01

    Full Text Available In order to study Hall effect in pure and CNT doped YBCO polycrystalline samples, we have measured longitudinal and transverse voltages at the different magnetic field (0-9T in the vortex state. We found a sign reversal for pure sample near 3T and double sign reversal of the Hall coefficient for CNT doped sample near 3 and 5T. It can be deduced that CNT doping caused strong flux pinning and Hall double sign reversal in this compound.

  12. Quantized Anomalous Hall Effect in Magnetic Topological Insulators

    Institute of Scientific and Technical Information of China (English)

    YU Rui

    2011-01-01

    The Hall effect, the anomalous Hall effect (AHE) and the spin Hall effect are thndamental transport processes in solids arising from the Lorentz force and the spin-orbit coupling respectively. The AHE, in which a voltage transverse to the electric current appears even in the absence of an external magnetic field, was first detected in ferromagnetic (FM) metals in 1881 and later found to arise from the spin-orbit coupling (SOC) between the current and magnetic moments.

  13. Kelvin-Helmholtz versus Hall magnetoshear instability in astrophysical flows.

    Science.gov (United States)

    Gómez, Daniel O; Bejarano, Cecilia; Mininni, Pablo D

    2014-05-01

    We study the stability of shear flows in a fully ionized plasma. Kelvin-Helmholtz is a well-known macroscopic and ideal shear-driven instability. In sufficiently low-density plasmas, also the microscopic Hall magnetoshear instability can take place. We performed three-dimensional simulations of the Hall-magnetohydrodynamic equations where these two instabilities are present, and carried out a comparative study. We find that when the shear flow is so intense that its vorticity surpasses the ion-cyclotron frequency of the plasma, the Hall magnetoshear instability is not only non-negligible, but it actually displays growth rates larger than those of the Kelvin-Helmholtz instability.

  14. From University Heights to Cooperstown: Halls of Fame and American Memory

    Science.gov (United States)

    Friss, Evan J.

    2005-01-01

    This article examines the development and function of American halls of fame as cultural memory institutions. By comparing the Hall of Fame for Great Americans with the National Baseball Hall of Fame, the author posits that halls of fame illuminate the ways in which cultural memory institutions can, through an archival process, preserve, instill,…

  15. Transnational Relations Between The BBC And The WDR (1960-1969: The Central Roles Of Hugh Greene And Klaus Von Bismarck

    Directory of Open Access Journals (Sweden)

    Christian Potschka

    2012-11-01

    Full Text Available This paper addresses the relationship between the BBC Director-General Hugh Carleton Greene and the director of the West German Broadcasting Corporation (WDR Klaus von Bismarck between 1960 and 1969. The thrust of the article is to point out the great potential of evaluating interpersonal relationships and their contribution to European perspectives on television history. The research is situated within transnational television historiography and it argues that the relationship between the two key personalities is manifested in multiple interdependencies, exchanges, visits and correspondences that exemplify the long-term British impact on the German broadcasting system as well as the bilateral cordial relations between the BBC and the WDR.

  16. Summer residence hall renovations focus on student comfort, environmental sustainability

    OpenAIRE

    DeLauder, Rachel

    2009-01-01

    With the majority of students home for the summer, Virginia Tech Housing Services has undertaken a variety of improvements and renovations in its residence halls aimed at increasing comfort and safety for students, while decreasing overall environmental impact.

  17. Segal-Bargmann-Hall Transform and Geometric Quantization

    Institute of Scientific and Technical Information of China (English)

    刘卫平; 王正栋; 胡大鹏

    2003-01-01

    @@ Using geometric methods, Hall has proved that the Segal-Bargmann transform for a con-nected Lie group K of compact type is an isometric isomorphism [H1] and is unique when Kis simply connected [H7].

  18. A High Performance Cathode Heater for Hall Thrusters Project

    Data.gov (United States)

    National Aeronautics and Space Administration — High current hollow cathodes are the baseline electron source for next generation high power Hall thrusters. Currently for electron sources providing current levels...

  19. Wellness: A Developmental Programming Model for Residence Halls.

    Science.gov (United States)

    Warner, Mark J.

    1985-01-01

    Demonstrates how a Wellness model can be an effective vehicle for promoting developmental programs in residence halls. The Wellness model is examined in terms of marketing, student development theory, and balanced programming. (BL)

  20. High Throughput Hall Thruster for Small Spacecraft Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Busek Co. Inc. proposes to develop a high throughput, nominal 100 W Hall Effect Thruster (HET). This HET will be sized for small spacecraft (< 180 kg), including...

  1. Magnesium Hall Thruster for Solar System Exploration Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The innovation being developed in this program is a Mg Hall Effect Thruster system that would open the door for In-Situ Resource Utilization based solar system...

  2. High Input Voltage Hall Thruster Discharge Converter Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The overall scope of this Phase I/II effort is the development of a high efficiency 15kW (nominal) Hall thruster discharge converter. In Phase I, Busek Co. Inc. will...

  3. High Throughput Hall Thruster for Small Spacecraft Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Busek is developing a high throughput nominal 100-W Hall Effect Thruster. This device is well sized for spacecraft ranging in size from several tens of kilograms to...

  4. The Dream Comes True in the Golden Hall

    Institute of Scientific and Technical Information of China (English)

    JianZhong; ChenJianguo

    2004-01-01

    Nanjing Traditional Music Ensemble has long dreamed of performing in Vienna's Golden Hall.Now the dream has come true.the whole troupe felt so exciting that they did not even sleep well during the flight.

  5. Mini array of quantum Hall devices based on epitaxial graphene

    Science.gov (United States)

    Novikov, S.; Lebedeva, N.; Hämäläinen, J.; Iisakka, I.; Immonen, P.; Manninen, A. J.; Satrapinski, A.

    2016-05-01

    Series connection of four quantum Hall effect (QHE) devices based on epitaxial graphene films was studied for realization of a quantum resistance standard with an up-scaled value. The tested devices showed quantum Hall plateaux RH,2 at a filling factor v = 2 starting from a relatively low magnetic field (between 4 T and 5 T) when the temperature was 1.5 K. The precision measurements of quantized Hall resistance of four QHE devices connected by triple series connections and external bonding wires were done at B = 7 T and T = 1.5 K using a commercial precision resistance bridge with 50 μA current through the QHE device. The results showed that the deviation of the quantized Hall resistance of the series connection of four graphene-based QHE devices from the expected value of 4×RH,2 = 2 h/e2 was smaller than the relative standard uncertainty of the measurement (resistance bridge.

  6. Magnesium Hall Thruster for Solar System Exploration Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Busek proposes to prove the feasibility of a Mg Hall effect thruster system that would open the door for In-Situ Resource Utilization (ISRU) based solar system...

  7. Pragmatic data fusion uncertainty concerns: Tribute to Dave L. Hall

    CSIR Research Space (South Africa)

    Blasch, E

    2016-07-01

    Full Text Available to knowledge acquisition and delivery. A summary of the uncertainty issues from Dave Hall, originating with the Joint Directors of the Laboratories (JDL) model, include these attributes across the JDL Levels which are: data (variance), object assessment...

  8. Hall Determination of Atomic Radii of Alkali Metals

    Science.gov (United States)

    Houari, Ahmed

    2008-01-01

    I will propose here an alternative method for determining atomic radii of alkali metals based on the Hall measurements of their free electron densities and the knowledge of their crystal structure. (Contains 2 figures.)

  9. Valleytronics. The valley Hall effect in MoS₂ transistors.

    Science.gov (United States)

    Mak, K F; McGill, K L; Park, J; McEuen, P L

    2014-06-27

    Electrons in two-dimensional crystals with a honeycomb lattice structure possess a valley degree of freedom (DOF) in addition to charge and spin. These systems are predicted to exhibit an anomalous Hall effect whose sign depends on the valley index. Here, we report the observation of this so-called valley Hall effect (VHE). Monolayer MoS2 transistors are illuminated with circularly polarized light, which preferentially excites electrons into a specific valley, causing a finite anomalous Hall voltage whose sign is controlled by the helicity of the light. No anomalous Hall effect is observed in bilayer devices, which have crystal inversion symmetry. Our observation of the VHE opens up new possibilities for using the valley DOF as an information carrier in next-generation electronics and optoelectronics.

  10. Fractional quantum Hall effect in the absence of Landau levels.

    Science.gov (United States)

    Sheng, D N; Gu, Zheng-Cheng; Sun, Kai; Sheng, L

    2011-07-12

    It is well known that the topological phenomena with fractional excitations, the fractional quantum Hall effect, will emerge when electrons move in Landau levels. Here we show the theoretical discovery of the fractional quantum Hall effect in the absence of Landau levels in an interacting fermion model. The non-interacting part of our Hamiltonian is the recently proposed topologically non-trivial flat-band model on a checkerboard lattice. In the presence of nearest-neighbouring repulsion, we find that at 1/3 filling, the Fermi-liquid state is unstable towards the fractional quantum Hall effect. At 1/5 filling, however, a next-nearest-neighbouring repulsion is needed for the occurrence of the 1/5 fractional quantum Hall effect when nearest-neighbouring repulsion is not too strong. We demonstrate the characteristic features of these novel states and determine the corresponding phase diagram.

  11. Hall Viscosity I: Linear Response Theory for Viscosity

    Science.gov (United States)

    Bradlyn, Barry; Goldstein, Moshe; Read, Nicholas

    2012-02-01

    In two dimensional systems with broken time-reversal symmetry, there can exist a non-dissipative viscosity coefficient [1,2,3]. This Hall viscosity is similar in nature to the non-dissipative Hall conductivity. In order to investigate this phenomenon further, we develop a linear response formalism for viscosity. We derive a Kubo formula for the frequency dependent viscosity tensor in the long wavelength limit. We compute the viscosity tensor for the free electron gas, integer quantum Hall systems, and two-dimensional paired superfluids. In the zero frequency limit, we show how the known results [3,4] for the Hall viscosity are recovered.[4pt] [1] J. Avron, R. Seiler, and P. Zograf, Phys. Rev. Lett. 75, 697 (1995).[0pt] [2] P. Levay, J. Math. Phys. 36, 2792 (1995).[0pt] [3] N. Read, Phys. Rev. B 79, 045308 (2009).[0pt] [4] N. Read and E. Rezayi, Phys. Rev. B 84, 085316 (2011).

  12. Global regularity for generalized Hall magneto-hydrodynamics systems

    Directory of Open Access Journals (Sweden)

    Renhui Wan

    2015-06-01

    Full Text Available In this article, we consider the tridimensional generalized Hall magneto-hydrodynamics (Hall-MHD system, with $(-\\Delta^\\alpha u$ and $(-\\Delta^\\beta b$. For $\\alpha\\ge 5/4$, $\\beta\\ge 7/4$, we obtain the global regularity of classical solutions. For $0<\\alpha<5/4$ and $1/2<\\beta<7/4$, with small data, the system also possesses global classical solutions. In addition, for the standard Hall-MHD system, $\\alpha=\\beta=1$, by adding a suitable condition, we give a positive answer to the open question in [3]. At last, we study the regularity criterions of generalized Hall-MHD system. In particular, we prove the regularity criterion in terms of horizontal gradient $\

  13. Phonon Hall Effect in Four-Terminal Junctions

    OpenAIRE

    Zhang, Lifa; Wang, Jian-Sheng; Li, Baowen

    2009-01-01

    Using an exact nonequilibrium Green's function formulism, the phonon Hall effect for paramagnetic dielectrics is studied in a four-terminal device setting. The temperature difference in the transverse direction of the heat current is calculated for two-dimensional models with the magnetic field perpendicular to the plane. We find a surprising result that the square lattice does not have the phonon Hall effect while a honeycomb lattice has. This can be explained by symmetry. The temperature di...

  14. Chern-Simons Dynamics and the Quantum Hall Effect

    CERN Document Server

    Balachandran, A P

    1991-01-01

    Theoretical developments during the past several years have shown that large scale properties of the Quantum Hall system can be successfully described by effective field theories which use the Chern-Simons interaction. In this article, we first recall certain salient features of the Quantum Hall Effect and their microscopic explanation. We then review one particular approach to their description based on the Chern-Simons Lagrangian and its variants.

  15. Spin and Isospin: Exotic Order in Quantum Hall Ferromagnets

    Science.gov (United States)

    Girvin, Steven M.

    Quantum mechanics is a strange business, and the quantum physics of strongly correlated many-electron systems can be stranger still. Good examples are the various quantum Hall effects. They are among the most remarkable many-body quantum phenomena discovered in the second half of the 20th century, comparable in intellectual import to superconductivity and superfluidity. The quantum Hall effects are an extremely rich set of phenomena with deep and truly fundamental theoretical implications...

  16. Hughes Associates Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Olson, Brad [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2013-05-22

    This report focuses on the more limiting gasket material (neoprene and viton). The use of polymer based gasketing material has led the DOE to question whether the ducts will be able to maintain structural integrity during a fire.

  17. Hall viscosity and electromagnetic response of electrons in graphene

    Science.gov (United States)

    Sherafati, Mohammad; Principi, Alessandro; Vignale, Giovanni

    2016-09-01

    We derive an analytic expression for the geometric Hall viscosity of noninteracting electrons in a single graphene layer in the presence of a perpendicular magnetic field. We show that a recently derived formula in C. Hoyos and D. T. Son [Phys. Rev. Lett. 108, 066805 (2012), 10.1103/PhysRevLett.108.066805], which connects the coefficient of q2 in the wave-vector expansion of the Hall conductivity σx y(q ) of the two-dimensional electron gas (2DEG) to the Hall viscosity and the orbital diamagnetic susceptibility of that system, continues to hold for graphene, in spite of the lack of Galilean invariance, with a suitable definition of the effective mass. We also show that, for a sufficiently large number of occupied Landau levels in the positive-energy sector, the Hall conductivity of electrons in graphene reduces to that of a Galilean-invariant 2DEG with an effective mass given by ℏ kF/vF (cyclotron mass). Even in the most demanding case, i.e., when the chemical potential falls between the zeroth and the first Landau levels, the cyclotron mass formula gives results accurate to better than 1%. The connection between the Hall conductivity and the viscosity provides a possible avenue to measure the Hall viscosity in graphene.

  18. Tunnelling anomalous and planar Hall effects (Conference Presentation)

    Science.gov (United States)

    Matos-Abiague, Alex; Scharf, Benedikt; Han, Jong E.; Hankiewicz, Ewelina M.; Zutic, Igor

    2016-10-01

    We theoretically show how the interplay between spin-orbit coupling (SOC) and magnetism can result in a finite tunneling Hall conductance, transverse to the applied bias. For two-dimensional tunnel junctions with a ferromagnetic lead and magnetization perpendicular to the current flow, the detected anomalous Hall voltage can be used to extract information not only about the spin polarization but also about the strength of the interfacial SOC. In contrast, a tunneling current across a ferromagnetic barrier on the surface of a three-dimensional topological insulator (TI) can induce a planar Hall response even when the magnetization is oriented along the current flow[1]. The tunneling nature of the states contributing to the planar Hall conductance can be switched from the ordinary to the Klein regimes by the electrostatic control of the barrier strength. This allows for an enhancement of the transverse response and a giant Hall angle, with the tunneling planar Hall conductance exceeding the longitudinal component. Despite the simplicity of a single ferromagnetic region, the TI/ferromagnet system exhibits a variety of functionalities. In addition to a spin-valve operation for magnetic sensing and storing information, positive, negative, and negative differential conductances can be tuned by properly adjusting the barrier potential and/or varying the magnetization direction. Such different resistive behaviors in the same system are attractive for potential applications in reconfigurable spintronic devices. [1] B. Scharf, A. Matos-Abiague, J. E. Han, E. M. Hankiewicz, and I. Zutic, arXiv:1601.01009 (2016).

  19. The quantum Hall's effect:A quantum electrodynamic phenomenon

    Institute of Scientific and Technical Information of China (English)

    A.I. Arbab

    2012-01-01

    We have applied Maxwell's equations to study the physics of quantum Hall's effect.The electromagnetic properties of this system are obtained.The Hall's voltage,VH =2πh2ns/e rn,where ns is the electron number density,for a 2-dimensional system,and h =2πh is the Planck's constant,is found to coincide with the voltage drop across the quantum capacitor.Consideration of the cyclotronic motion of electrons is found to give rise to Hall's resistance.Ohmic resistances in the horizontal and vertical directions have been found to exist before equilibrium state is reached.At a fundamental level,the Hall's effect is found to be equivalent to a resonant LCR circuit with LH =2π m/e2ns and CH =me2/2πh2ns satisfying the resonance condition with resonant frequency equal to the inverse of the scattering (relaxation) time,Ts.The Hall's resistance is found to be RH =√LH/CH.The Hall's resistance may be connected with the impedance that the electron wave experiences when it propagates in the 2-dimeasional gas.

  20. Magnetometry of micro-magnets with electrostatically defined Hall bars

    Energy Technology Data Exchange (ETDEWEB)

    Lachance-Quirion, Dany; Camirand Lemyre, Julien; Bergeron, Laurent; Sarra-Bournet, Christian [Département de Physique, Université de Sherbrooke, J1K 2R1 Sherbrooke, Québec (Canada); Pioro-Ladrière, Michel, E-mail: michel.pioro-ladriere@usherbrooke.ca [Département de Physique, Université de Sherbrooke, J1K 2R1 Sherbrooke, Québec (Canada); CIFAR Program in Quantum Information Science, Canadian Institute for Advanced Research (CIFAR), M5G 1Z8 Toronto, Ontario (Canada)

    2015-11-30

    Micro-magnets are key components for quantum information processing with individual spins, enabling arbitrary rotations and addressability. In this work, characterization of sub-micrometer sized CoFe ferromagnets is performed with Hall bars electrostatically defined in a two-dimensional electron gas. Due to the ballistic nature of electron transport in the cross junction of the Hall bar, anomalies such as the quenched Hall effect appear near zero external magnetic field, thus hindering the sensitivity of the magnetometer to small magnetic fields. However, it is shown that the sensitivity of the diffusive limit can be almost completely restored at low temperatures using a large current density in the Hall bar of about 10 A/m. Overcoming the size limitation of conventional etched Hall bars with electrostatic gating enables the measurement of magnetization curves of 440 nm wide micro-magnets with a signal-to-noise ratio above 10{sup 3}. Furthermore, the inhomogeneity of the stray magnetic field created by the micro-magnets is directly measured using the gate-voltage-dependent width of the sensitive area of the Hall bar.

  1. Giant Hall Photoconductivity in Narrow-Gapped Dirac Materials.

    Science.gov (United States)

    Song, Justin C W; Kats, Mikhail A

    2016-12-14

    Carrier dynamics acquire a new character in the presence of Bloch-band Berry curvature, which naturally arises in gapped Dirac materials (GDMs). Here, we argue that photoresponse in GDMs with small band gaps is dramatically enhanced by Berry curvature. This manifests in a giant and saturable Hall photoconductivity when illuminated by circularly polarized light. Unlike Hall motion arising from a Lorentz force in a magnetic field, which impedes longitudinal carrier motion, Hall photoconductivity arising from Berry curvature can boost longitudinal carrier transport. In GDMs, this results in a helicity-dependent photoresponse in the Hall regime, where photoconductivity is dominated by its Hall component. We find that the induced Hall conductivity per incident irradiance is enhanced by up to 6 orders of magnitude when moving from the visible regime (with corresponding band gaps) to the far infrared. These results suggest that narrow-gap GDMs are an ideal test-bed for the unique physics that arise in the presence of Berry curvature and open a new avenue for infrared and terahertz optoelectronics.

  2. The spin Hall effect in a quantum gas.

    Science.gov (United States)

    Beeler, M C; Williams, R A; Jiménez-García, K; LeBlanc, L J; Perry, A R; Spielman, I B

    2013-06-13

    Electronic properties such as current flow are generally independent of the electron's spin angular momentum, an internal degree of freedom possessed by quantum particles. The spin Hall effect, first proposed 40 years ago, is an unusual class of phenomena in which flowing particles experience orthogonally directed, spin-dependent forces--analogous to the conventional Lorentz force that gives the Hall effect, but opposite in sign for two spin states. Spin Hall effects have been observed for electrons flowing in spin-orbit-coupled materials such as GaAs and InGaAs (refs 2, 3) and for laser light traversing dielectric junctions. Here we observe the spin Hall effect in a quantum-degenerate Bose gas, and use the resulting spin-dependent Lorentz forces to realize a cold-atom spin transistor. By engineering a spatially inhomogeneous spin-orbit coupling field for our quantum gas, we explicitly introduce and measure the requisite spin-dependent Lorentz forces, finding them to be in excellent agreement with our calculations. This 'atomtronic' transistor behaves as a type of velocity-insensitive adiabatic spin selector, with potential application in devices such as magnetic or inertial sensors. In addition, such techniques for creating and measuring the spin Hall effect are clear prerequisites for engineering topological insulators and detecting their associated quantized spin Hall effects in quantum gases. As implemented, our system realizes a laser-actuated analogue to the archetypal semiconductor spintronic device, the Datta-Das spin transistor.

  3. Anisotropic intrinsic spin Hall effect in quantum wires.

    Science.gov (United States)

    Cummings, A W; Akis, R; Ferry, D K

    2011-11-23

    We use numerical simulations to investigate the spin Hall effect in quantum wires in the presence of both Rashba and Dresselhaus spin-orbit coupling. We find that the intrinsic spin Hall effect is highly anisotropic with respect to the orientation of the wire, and that the nature of this anisotropy depends strongly on the electron density and the relative strengths of the Rashba and Dresselhaus spin-orbit couplings. In particular, at low densities, when only one subband of the quantum wire is occupied, the spin Hall effect is strongest for electron momentum along the [N110] axis, which is the opposite of what is expected for the purely 2D case. In addition, when more than one subband is occupied, the strength and anisotropy of the spin Hall effect can vary greatly over relatively small changes in electron density, which makes it difficult to predict which wire orientation will maximize the strength of the spin Hall effect. These results help to illuminate the role of quantum confinement in spin-orbit-coupled systems, and can serve as a guide for future experimental work on the use of quantum wires for spin-Hall-based spintronic applications.

  4. Planar Hall magnetoresistive aptasensor for thrombin detection.

    Science.gov (United States)

    Sinha, B; Ramulu, T S; Kim, K W; Venu, R; Lee, J J; Kim, C G

    2014-09-15

    The use of aptamer-based assays is an emerging and attractive approach in disease research and clinical diagnostics. A sensitive aptamer-based sandwich-type sensor is presented to detect human thrombin using a planar Hall magnetoresistive (PHR) sensor in cooperation with superparamagnetic labels. A PHR sensor has the great advantages of a high signal-to-noise ratio, a small offset voltage and linear response in the low-field region, allowing it to act as a high-resolution biosensor. In the system presented here, the sensor has an active area of 50 µm × 50 µm with a 10-nm gold layer deposited onto the sensor surface prior to the binding of thiolated DNA primary aptamer. A polydimethylsiloxane well of 600-µm radius and 1-mm height was prepared around the sensor surface to maintain the same specific area and volume for each sensor. The sensor response was traced in real time upon the addition of streptavidin-functionalized magnetic labels on the sensor. A linear response to the thrombin concentration in the range of 86 pM-8.6 µM and a lower detection limit down to 86 pM was achieved by the proposed present method with a sample volume consumption of 2 µl. The proposed aptasensor has a strong potential for application in clinical diagnosis.

  5. Acoustics in Halls for Speech and Music

    Science.gov (United States)

    Gade, Anders C.

    This chapter deals specifically with concepts, tools, and architectural variables of importance when designing auditoria for speech and music. The focus will be on cultivating the useful components of the sound in the room rather than on avoiding noise from outside or from installations, which is dealt with in Chap. 11. The chapter starts by presenting the subjective aspects of the room acoustic experience according to consensus at the time of writing. Then follows a description of their objective counterparts, the objective room acoustic parameters, among which the classical reverberation time measure is only one of many, but still of fundamental value. After explanations on how these parameters can be measured and predicted during the design phase, the remainder of the chapter deals with how the acoustic properties can be controlled by the architectural design of auditoria. This is done by presenting the influence of individual design elements as well as brief descriptions of halls designed for specific purposes, such as drama, opera, and symphonic concerts. Finally, some important aspects of loudspeaker installations in auditoria are briefly touched upon.

  6. Brand new hall in the main building

    CERN Multimedia

    Corinne Pralavorio

    2014-01-01

    The renovation of the UNIQA and post office premises is getting under way, with their reopening scheduled for the spring.   The renovation of the large hall in the main building (Building 500) has finally reached the home straight. As of this week, building contractors will get to work on the last part – the offices of UNIQA and La Poste. In the last week of November, the two concessions moved their offices across Route Scherrer to the same part of Building 510 where UBS was temporarily housed during the bank’s refurbishment. Their services were therefore unavailable for one day. The renovation work will last until the spring, with the new offices expected to open in May 2015. Between now and then, the windows and insulation will be completely refitted, with a view to reducing heat loss considerably, and, above all, the premises will be modernised to improve customer reception and service. For example, UNIQA’s new premises will feature a confidential area, guarantee...

  7. The integer quantum hall effect revisited

    Energy Technology Data Exchange (ETDEWEB)

    Michalakis, Spyridon [Los Alamos National Laboratory; Hastings, Matthew [Q STATION, CALIFORNIA

    2009-01-01

    For T - L x L a finite subset of Z{sup 2}, let H{sub o} denote a Hamiltonian on T with periodic boundary conditions and finite range, finite strength intetactions and a unique ground state with a nonvanishing spectral gap. For S {element_of} T, let q{sub s} denote the charge at site s and assume that the total charge Q = {Sigma}{sub s {element_of} T} q{sub s} is conserved. Using the local charge operators q{sub s}, we introduce a boundary magnetic flux in the horizontal and vertical direction and allow the ground state to evolve quasiadiabatically around a square of size one magnetic flux, in flux space. At the end of the evolution we obtain a trivial Berry phase, which we compare, via a method reminiscent of Stokes Theorem. to the Berry phase obtained from an evolution around an exponentially small loop near the origin. As a result, we show, without any averaging assumption, that the Hall conductance is quantized in integer multiples of e{sup 2}/h up to exponentially small corrections of order e{sup -L/{zeta}}, where {zeta}, is a correlation length that depends only on the gap and the range and strength of the interactions.

  8. Magnetized Epsilon-Near-Zero (ENZ) Structures: Hall Opacity, Hall Transparency, and One-Way Photonic Surface States

    CERN Document Server

    Davoyan, Arthur

    2013-01-01

    We study propagation of transverse-magnetic (TM) electromagnetic waves in the bulk and at the surface of magnetized epsilon-near-zero (ENZ) medium in a Voigt configuration. We reveal that in a certain range of material parameters novel regimes of wave propagation emerge: we show that the transparency of the medium can be altered with the magnetization leading either to magnetically induced Hall opacity or Hall transparency of the ENZ. In our theoretical study, we demonstrate that surface waves at the interface between either a transparent or an opaque Hall medium and a homogeneous medium may, under certain conditions, be predominantly one-way. Moreover, we predict that one-way photonic surface states may exist at the interface of an opaque Hall ENZ and a regular metal, giving rise to a possibility for backscattering immune wave propagation and isolation.

  9. Numerical analysis of Hall effect on the performance of magnetohydrodynamic heat shield system based on nonequilibrium Hall parameter model

    Science.gov (United States)

    Li, Kai; Liu, Jun; Liu, Weiqiang

    2017-01-01

    Magnetohydrodynamic (MHD) heat shield system, a novel thermal protection technique in the hypersonic field, has been paid much attention in recent years. In the real flight condition, not only the Lorentz force but also the Hall electric field is induced by the interaction between ionized air post shock and magnetic field. In order to analyze the action mechanisms of the Hall effect, numerical methods of coupling thermochemical nonequilibrium flow field with externally applied magnetic field as well as the induced electric field are constructed and validated. Based on the nonequilibrium model of Hall parameter, numerical simulations of the MHD heat shield system is conducted under two different magnetic induction strengths (B0=0.2 T, 0.5 T) on a reentry capsule forebody. Results show that, the Hall effect is the same under the two magnetic induction strengths when the wall is assumed to be conductive. For this case, with the Hall effect taken into account, the Lorentz force counter stream diminishes a lot and the circumferential component dominates, resulting that the heat flux and shock-off distance approach the case without MHD control. However, for the insulating wall, the Hall effect acts in different ways under these two magnetic induction strengths. For this case, with the Hall effect taken into account, the performance of MHD heat shield system approaches the case neglecting the Hall effect when B0 equals 0.2 T. Such performance becomes worse when B0 equals 0.5 T and the aerothermal environment on the capsule shoulder is even worse than the case without MHD control.

  10. Observational evidence for Hall drift and Hall waves in the crusts of isolated young neutron stars

    CERN Document Server

    Xie, Yi

    2013-01-01

    The observed long-term spin-down evolution of isolated radio pulsars cannot be explained by the standard magnetic dipole radiation with a constant braking torque. However how and why the torque varies still remains controversial, which is an outstanding problem in our understanding of neutron stars. Many pulsars have been observed with significant long-term changes of their spin-down rates modulated by quasi-periodic oscillations. Applying the phenomenological model of pulsar timing noise we developed recently to the observed precise pulsar timing data, here we show that, the Hall drift and Hall waves in their crusts are responsible for the observed long-term evolution of the spin-down rates and their quasi-periodic modulations, respectively. Consequently the majority of dipolar magnetic field lines are restricted to their outer crusts, rather than penetrating the cores of the neutron stars. Understanding of the nature of pulsar timing noise not only reveals the interior physics of neutron stars, but also all...

  11. Analysis of Lipid Experiments (ALEX)

    DEFF Research Database (Denmark)

    Husen, Peter; Tarasov, Kirill; Katafiasz, Maciej

    2013-01-01

    Global lipidomics analysis across large sample sizes produces high-content datasets that require dedicated software tools supporting lipid identification and quantification, efficient data management and lipidome visualization. Here we present a novel software-based platform for streamlined data ...

  12. Alex Woloch, Caratterizzazione e distribuzione

    Directory of Open Access Journals (Sweden)

    Sostene Massimo Zangari

    2012-12-01

    Full Text Available Le opere narrative mostrano un’innata consapevolezza della tensione che deriva dalla necessità di distribuire l’attenzione su diversi personaggi in quantità disomogenee. L’autore si propone di creare un modello teorico per affrontare una serie di questioni legate alle scelte distribuzionali nel romanzo dell’Ottocento. Vengono introdotte le categorie di spazio-personaggio – l’incontro/scontro tra individuo rappresentato e spazio narrativo – e sistema-personaggi – la disposizione di personaggi multipli in una struttura narrativa. Le categorie intendono ovviare alla scissione che ha dominato la critica sul personaggio, divisa tra due posizioni antitetiche: da un lato chi ha ridotto il personaggio a mero accorgimento formale, dall’altro coloro i quali ne hanno enfatizzato l’aspetto referenziale e umano. L’intento delle categorie qui proposte è invece quello di recuperare la dialettica che lega questi due aspetti del personaggio finzionale. In particolare, mettere in evidenza come gli esiti strutturali del romanzo dipendano dal problema di rappresentare personaggi minori ridotti ai due principali paradigmi del bizzaro e del lavoratore. I meccanismi del romanzo e i disequilibri strutturali che derivano dall’incorporazione dei personaggi sono interpretati dall’autore come rispechiamento del difficile rapporto tra diseguaglianza e democrazia, che ha contrassegnato un secolo, l’Ottocento, dove alla mobilità sociale della borghesia faceva da contraltare la marginalizzazione delle classi subalterne. L’intervento si conclude con cenni al trattamento del personaggio nei lavori di Jane Austen, Dickens e Balzac.

  13. Alex McQueen : power

    Index Scriptorium Estoniae

    1998-01-01

    A. McQueeni moevälisest tegevusest. 'American Express' tellis temalt krediitkaardi kujunduse. 1998. a. suvest ajakirja 'Dazed & Confused' abitoimetaja. A. McQueen on lubanud olla Björki (Island) video kunstiline juht.

  14. Eigenanalysis of Ideal Hall MHD Turbulence

    Science.gov (United States)

    Fu, T.; Shebalin, J. V.

    2011-12-01

    Ideal, incompressible, homogeneous, Hall magnetohydrodynamic (HMHD) turbulence may be investigated through a Fourier spectral method. In three-dimensional periodic geometry, the independent Fourier coefficients represent a canonical ensemble described by a Gaussian probability density. The canonical ensemble is based on the conservation of three invariants: total energy, generalized helicity, and magnetic helicity. Generalized helicity in HMHD takes the place of cross helicity in MHD. The invariants determine the modal probability density giving the spectral structure and equilibrium statistics of ideal HMHD, which are compared to known MHD results. New results in absolute equilibrium ensemble theory are derived using a novel approach that involves finding the eigenvalues of a Hermitian covariance matrix for each modal probability density. The associated eigenvectors transform the original phase space variables into eigenvariables through a special unitary transformation. These are the normal modes which facilitate the analysis of ideal HMHD non-linear dynamics. The eigenanalysis predicts that the low wavenumber modes with very small eigenvalues may have mean values that are large compared to their standard deviations, contrary to the ideal ensemble prediction of zero mean values. (Expectation values may also be relatively large at the highest wave numbers, but the addition of even small levels of dissipation removes any relevance this may have for real-world turbulence.) This behavior is non-ergodic over very long times for a numerical simulation and is termed 'broken ergodicity'. For fixed values of the ideal invariants, the effect is seen to be enhanced with increased numerical grid size. Broken ergodicity at low wave number modes gives rise to large-scale, quasi-stationary, coherent structure. Physically, this corresponds to plasma relaxation to force-free states. For real HMHD turbulence with dissipation, broken ergodicity and coherent structure are still

  15. Azimuthal Spoke Propagation in Hall Effect Thrusters

    Science.gov (United States)

    Sekerak, Michael J.; Longmier, Benjamin W.; Gallimore, Alec D.; Brown, Daniel L.; Hofer, Richard R.; Polk, James E.

    2013-01-01

    Spokes are azimuthally propagating perturbations in the plasma discharge of Hall Effect Thrusters (HETs) that travel in the E x B direction and have been observed in many different systems. The propagation of azimuthal spokes are investigated in a 6 kW HET known as the H6 using ultra-fast imaging and azimuthally spaced probes. A spoke surface is a 2-D plot of azimuthal light intensity evolution over time calculated from 87,500 frames/s videos. The spoke velocity has been determined using three methods with similar results: manual fitting of diagonal lines on the spoke surface, linear cross-correlation between azimuthal locations and an approximated dispersion relation. The spoke velocity for three discharge voltages (300, 400 and 450 V) and three anode mass flow rates (14.7, 19.5 and 25.2 mg/s) yielded spoke velocities between 1500 and 2200 m/s across a range of normalized magnetic field settings. The spoke velocity was inversely dependent on magnetic field strength for low B-field settings and asymptoted at B-field higher values. The velocities and frequencies are compared to standard drifts and plasma waves such as E x B drift, electrostatic ion cyclotron, magnetosonic and various drift waves. The empirically approximated dispersion relation yielded a characteristic velocity that matched the ion acoustic speed for 5 eV electrons that exist in the near-anode and near-field plume regions of the discharge channel based on internal measurements. Thruster performance has been linked to operating mode where thrust-to-power is maximized when azimuthal spokes are present so investigating the underlying mechanism of spokes will benefit thruster operation.

  16. Mode Transitions in Hall Effect Thrusters

    Science.gov (United States)

    Sekerak, Michael J.; Longmier, Benjamin W.; Gallimore, Alec D.; Brown, Daniel L.; Hofer, Richard R.; Polk, James E.

    2013-01-01

    Mode transitions have been commonly observed in Hall Effect Thruster (HET) operation where a small change in a thruster operating parameter such as discharge voltage, magnetic field or mass flow rate causes the thruster discharge current mean value and oscillation amplitude to increase significantly. Mode transitions in a 6-kW-class HET called the H6 are induced by varying the magnetic field intensity while holding all other operating parameters constant and measurements are acquired with ion saturation probes and ultra-fast imaging. Global and local oscillation modes are identified. In the global mode, the entire discharge channel oscillates in unison and azimuthal perturbations (spokes) are either absent or negligible. Downstream azimuthally spaced probes show no signal delay between each other and are very well correlated to the discharge current signal. In the local mode, signals from the azimuthally spaced probes exhibit a clear delay indicating the passage of "spokes" and are not well correlated to the discharge current. These spokes are localized oscillations propagating in the ExB direction that are typically 10-20% of the mean value. In contrast, the oscillations in the global mode can be 100% of the mean value. The transition between global and local modes occurs at higher relative magnetic field strengths for higher mass flow rates or higher discharge voltages. The thrust is constant through mode transition but the thrust-to-power decreased by 25% due to increasing discharge current. The plume shows significant differences between modes with the global mode significantly brighter in the channel and the near-field plasma plume as well as exhibiting a luminous spike on thruster centerline. Mode transitions provide valuable insight to thruster operation and suggest improved methods for thruster performance characterization.

  17. High temperature Hall measurement setup for thin film characterization

    Science.gov (United States)

    Adnane, L.; Gokirmak, A.; Silva, H.

    2016-07-01

    Hall measurement using the van der Pauw technique is a common characterization approach that does not require patterning of contacts. Measurements of the Hall voltage and electrical resistivity lead to the product of carrier mobility and carrier concentration (Hall coefficient) which can be decoupled through transport models. Based on the van der Paw method, we have developed an automated setup for Hall measurements from room temperature to ˜500 °C of semiconducting thin films of a wide resistivity range. The resistivity of the film and Hall coefficient is obtained from multiple current-voltage (I-V) measurements performed using a semiconductor parameter analyzer under applied constant "up," zero, and "down" magnetic field generated with two neodymium permanent magnets. The use of slopes obtained from multiple I-Vs for the three magnetic field conditions offer improved accuracy. Samples are preferred in square shape geometry and can range from 2 mm to 25 mm side length. Example measurements of single-crystal silicon with known doping concentration show the accuracy and reliability of the measurement.

  18. Stability of Hall equilibria in neutron star crusts

    CERN Document Server

    Marchant, Pablo; Valdivia, Juan Alejandro; Hoyos, Jaime H

    2014-01-01

    In the solid crusts of neutron stars, the advection of the magnetic field by the current-carrying electrons, an effect known as Hall drift, should play a very important role as the ions remain essentially fixed (as long as the solid does not break). Although Hall drift preserves the magnetic field energy, it has been argued that it may drive a turbulent cascade to scales at which Ohmic dissipation becomes effective, allowing a much faster decay in objects with very strong fields. On the other hand, it has been found that there are "Hall equilibria", i.e., field configurations that are unaffected by Hall drift. Here, we address the crucial question of the stability of these equilibria through axially symmetric (2D) numerical simulations of Hall drift and Ohmic diffusion, with the simplifying assumption of uniform electron density and conductivity. We demonstrate the 2D-stability of a purely poloidal equilibrium, for which Ohmic dissipation makes the field evolve towards an attractor state through adjacent stab...

  19. Suitable reverberation times for halls for rock and pop music.

    Science.gov (United States)

    Adelman-Larsen, Niels Werner; Thompson, Eric R; Gade, Anders C

    2010-01-01

    The existing body of literature regarding the acoustic design of concert halls has focused almost exclusively on classical music, although there are many more performances of popular music, including rock and pop. Objective measurements were made of the acoustics of 20 rock music venues in Denmark and a questionnaire was used in a subjective assessment of those venues with professional rock musicians and sound engineers as expert listeners. Correlations between the measurements show that clarity, including bass frequencies down to 63 Hz, is important for the general impression of the acoustics of the hall. The best-rated halls in the study have reverberation times that are approximately frequency independent from 0.6 to 1.2 s for hall volumes from 1000 to 6000 m(3). The worst rated halls in the study had significantly higher reverberation times in the 63 and 125 Hz bands. Since most audiences at rock concerts are standing, absorption coefficients were measured with a standing audience from 63 Hz to 4 kHz. These measurements showed that a standing audience absorbs about five times as much energy in mid-/high-frequency bands as in low-frequency bands.

  20. Reconnection dynamics with secondary tearing instability in compressible Hall plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Z. W., E-mail: zwma@zju.edu.cn; Wang, L. C.; Li, L. J. [Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou 310027 (China)

    2015-06-15

    The dynamics of a secondary tearing instability is systematically investigated based on compressible Hall magnetohydrodynamic. It is found that in the early nonlinear phase of magnetic reconnection before onset of the secondary tearing instability, the geometry of the magnetic field in the reconnection region tends to form a Y-type structure in a weak Hall regime, instead of an X-type structure in a strong Hall regime. A new scaling law is found that the maximum reconnection rate in the early nonlinear stage is proportional to the square of the ion inertial length (γ∝d{sub i}{sup 2}) in the weak Hall regime. In the late nonlinear phase, the thin elongated current sheet associated with the Y-type geometry of the magnetic field breaks up to form a magnetic island due to a secondary tearing instability. After the onset of the secondary tearing mode, the reconnection rate is substantially boosted by the formation of the X-type geometries of magnetic field in the reconnection regions. With a strong Hall effect, the maximum reconnection rate linearly increases with the increase of the ion inertial length (γ∝d{sub i})

  1. The local nature of incompressibility of quantum Hall effect

    Science.gov (United States)

    Kendirlik, E. M.; Sirt, S.; Kalkan, S. B.; Ofek, N.; Umansky, V.; Siddiki, A.

    2017-01-01

    Since the experimental realization of the integer quantum Hall effect in a two-dimensional electron system, the interrelation between the conductance quantization and the topological properties of the system has been investigated. Assuming that the two-dimensional electron system is described by a Bloch Hamiltonian, system is insulating in the bulk of sample throughout the quantum Hall plateau due to a magnetic field induced energy gap. Meanwhile, the system is conducting at the edges resembling a 2+1 dimensional topological insulator without time-reversal symmetry. Here, by our magneto-transport measurements performed on GaAs/AlGaAs high purity Hall bars with two inner contacts we show that incompressible strips formed at the edges result in Hall quantization, even if the bulk is compressible. Consequently, the relationship between the quantum Hall effect and topological bulk insulator breaks for specific field intervals within the plateaus. The measurement of conducting bulk, strongly challenges all existing single-particle theories. PMID:28071652

  2. Higher (odd dimensional quantum Hall effect and extended dimensional hierarchy

    Directory of Open Access Journals (Sweden)

    Kazuki Hasebe

    2017-07-01

    Full Text Available We demonstrate dimensional ladder of higher dimensional quantum Hall effects by exploiting quantum Hall effects on arbitrary odd dimensional spheres. Non-relativistic and relativistic Landau models are analyzed on S2k−1 in the SO(2k−1 monopole background. The total sub-band degeneracy of the odd dimensional lowest Landau level is shown to be equal to the winding number from the base-manifold S2k−1 to the one-dimension higher SO(2k gauge group. Based on the chiral Hopf maps, we clarify the underlying quantum Nambu geometry for odd dimensional quantum Hall effect and the resulting quantum geometry is naturally embedded also in one-dimension higher quantum geometry. An origin of such dimensional ladder connecting even and odd dimensional quantum Hall effects is illuminated from a viewpoint of the spectral flow of Atiyah–Patodi–Singer index theorem in differential topology. We also present a BF topological field theory as an effective field theory in which membranes with different dimensions undergo non-trivial linking in odd dimensional space. Finally, an extended version of the dimensional hierarchy for higher dimensional quantum Hall liquids is proposed, and its relationship to quantum anomaly and D-brane physics is discussed.

  3. Higher (odd) dimensional quantum Hall effect and extended dimensional hierarchy

    Science.gov (United States)

    Hasebe, Kazuki

    2017-07-01

    We demonstrate dimensional ladder of higher dimensional quantum Hall effects by exploiting quantum Hall effects on arbitrary odd dimensional spheres. Non-relativistic and relativistic Landau models are analyzed on S 2 k - 1 in the SO (2 k - 1) monopole background. The total sub-band degeneracy of the odd dimensional lowest Landau level is shown to be equal to the winding number from the base-manifold S 2 k - 1 to the one-dimension higher SO (2 k) gauge group. Based on the chiral Hopf maps, we clarify the underlying quantum Nambu geometry for odd dimensional quantum Hall effect and the resulting quantum geometry is naturally embedded also in one-dimension higher quantum geometry. An origin of such dimensional ladder connecting even and odd dimensional quantum Hall effects is illuminated from a viewpoint of the spectral flow of Atiyah-Patodi-Singer index theorem in differential topology. We also present a BF topological field theory as an effective field theory in which membranes with different dimensions undergo non-trivial linking in odd dimensional space. Finally, an extended version of the dimensional hierarchy for higher dimensional quantum Hall liquids is proposed, and its relationship to quantum anomaly and D-brane physics is discussed.

  4. Spin Hall effects in mesoscopic Pt films with high resistivity

    Science.gov (United States)

    Qin, Chuan; Luo, Yongming; Zhou, Chao; Cai, Yunjiao; Jia, Mengwen; Chen, Shuhan; Wu, Yizheng; Ji, Yi

    2016-10-01

    The energy efficiency of the spin Hall effects (SHE) can be enhanced if the electrical conductivity is decreased without sacrificing the spin Hall conductivity. The resistivity of Pt films can be increased to 150-300 µΩ · cm by mesoscopic lateral confinement, thereby decreasing the conductivity. The SHE and inverse spin Hall effects (ISHE) in these mesoscopic Pt films are explored at 10 K by using the nonlocal spin injection/detection method. All relevant physical quantities are determined in situ on the same substrate, and a quantitative approach is developed to characterize all processes effectively. Extensive measurements with various Pt thickness values reveal an upper limit for the Pt spin diffusion length: {λ\\text{pt}}   ⩽  0.8 nm. The average product of {λ\\text{pt}} and the Pt spin Hall angle {α\\text{H}} is substantial: {α\\text{H}}{λ\\text{pt}}   =  (0.142  ±  0.040) nm for 4 nm thick Pt, though a gradual decrease is observed at larger Pt thickness. The results suggest enhanced spin Hall effects in resistive mesoscopic Pt films.

  5. Concert halls with strong lateral reflections enhance musical dynamics.

    Science.gov (United States)

    Pätynen, Jukka; Tervo, Sakari; Robinson, Philip W; Lokki, Tapio

    2014-03-25

    One of the most thrilling cultural experiences is to hear live symphony-orchestra music build up from a whispering passage to a monumental fortissimo. The impact of such a crescendo has been thought to depend only on the musicians' skill, but here we show that interactions between the concert-hall acoustics and listeners' hearing also play a major role in musical dynamics. These interactions contribute to the shoebox-type concert hall's established success, but little prior research has been devoted to dynamic expression in this three-part transmission chain as a complete system. More forceful orchestral playing disproportionately excites high frequency harmonics more than those near the note's fundamental. This effect results in not only more sound energy, but also a different tone color. The concert hall transmits this sound, and the room geometry defines from which directions acoustic reflections arrive at the listener. Binaural directional hearing emphasizes high frequencies more when sound arrives from the sides of the head rather than from the median plane. Simultaneously, these same frequencies are emphasized by higher orchestral-playing dynamics. When the room geometry provides reflections from these directions, the perceived dynamic range is enhanced. Current room-acoustic evaluation methods assume linear behavior and thus neglect this effect. The hypothesis presented here is that the auditory excitation by reflections is emphasized with an orchestra forte most in concert halls with strong lateral reflections. The enhanced dynamic range provides an explanation for the success of rectangularly shaped concert-hall geometry.

  6. NASA HERMeS Hall Thruster Electrical Configuration Characterization

    Science.gov (United States)

    Peterson, Peter Y.; Kamhawi, Hani; Huang, Wensheng; Yim, John; Herman, Daniel; Williams, George; Gilland, James; Hofer, Richard

    2015-01-01

    The NASA Hall Effect Rocket with Magnetic Shielding (HERMeS) 12.5 kW Technology Demonstration Unit-1 (TDU-1) Hall thruster has been the subject of extensive technology maturation in preparation for development into a flight ready propulsion system. Part of the technology maturation was to test the TDU-1 thruster in several ground based electrical configurations to assess the thruster robustness and suitability to successful in-space operation. The ground based electrical configuration testing has recently been demonstrated as an important step in understanding and assessing how a Hall thruster may operate differently in-space compared to ground based testing, and to determine the best configuration to conduct development and qualification testing. This paper describes the electrical configuration testing of the HERMeS TDU-1 Hall thruster in NASA Glenn Research Center's Vacuum Facility 5. The three electrical configurations examined were 1) thruster body tied to facility ground, 2) thruster floating, and 3) thruster body electrically tied to cathode common. The HERMeS TDU-1 Hall thruster was also configured with two different exit plane boundary conditions, dielectric and conducting, to examine the influence on the electrical configuration characterization.

  7. The local nature of incompressibility of quantum Hall effect

    Science.gov (United States)

    Kendirlik, E. M.; Sirt, S.; Kalkan, S. B.; Ofek, N.; Umansky, V.; Siddiki, A.

    2017-01-01

    Since the experimental realization of the integer quantum Hall effect in a two-dimensional electron system, the interrelation between the conductance quantization and the topological properties of the system has been investigated. Assuming that the two-dimensional electron system is described by a Bloch Hamiltonian, system is insulating in the bulk of sample throughout the quantum Hall plateau due to a magnetic field induced energy gap. Meanwhile, the system is conducting at the edges resembling a 2+1 dimensional topological insulator without time-reversal symmetry. Here, by our magneto-transport measurements performed on GaAs/AlGaAs high purity Hall bars with two inner contacts we show that incompressible strips formed at the edges result in Hall quantization, even if the bulk is compressible. Consequently, the relationship between the quantum Hall effect and topological bulk insulator breaks for specific field intervals within the plateaus. The measurement of conducting bulk, strongly challenges all existing single-particle theories.

  8. Nonlinear Quantum Hall effects in Rarita-Schwinger gas

    CERN Document Server

    Luo, Xi; Wan, Xiangang; Yu, Yue

    2016-01-01

    Emergence of higher spin relativistic fermionic materials becomes a new favorite in the study of condensed matter physics. Massive Rarita-Schwinger 3/2-spinor was known owning very exotic properties, such as the superluminal fermionic modes and even being unstable in an external magnetic field. Due to the superluminal modes and the non-trivial constraints on the Rarita-Schwinger gas, we exposit anomalous properties of the Hall effects in (2+1)-dimensions which subvert the well-known quantum Hall paradigms. First, the Hall conductance of a pure Rarita-Schwinger gas is step-like but not plateau-quantized, instead of the linear dependence on the filling factor for a pure spin-1/2 Dirac gas. In reality, the Hall conductance of the Dirac gas is of quantized integer plateaus with the unit $\\frac{e^2}h$ due to the localization away from the Landau level centers. If the general localization rule is applicable to the disordered Rarita-Schwinger gas, the Hall plateaus are also expected to appear but they are nonlinearl...

  9. Spin Hall torques generated by rare-earth thin films

    Science.gov (United States)

    Reynolds, Neal; Jadaun, Priyamvada; Heron, John T.; Jermain, Colin L.; Gibbons, Jonathan; Collette, Robyn; Buhrman, R. A.; Schlom, D. G.; Ralph, D. C.

    2017-02-01

    We report an initial experimental survey of spin Hall torques generated by the rare-earth metals Gd, Dy, Ho, and Lu, along with comparisons to first-principles calculations of their spin Hall conductivities. Using spin torque ferromagnetic resonance (ST-FMR) measurements and dc-biased ST-FMR, we estimate lower bounds for the spin Hall torque ratio, ξSH, of ≈0.04 for Gd, ≈0.05 for Dy, ≈0.14 for Ho, and ≈0.014 for Lu. The variations among these elements are qualitatively consistent with results from first principles [density-functional theory (DFT) in the local density approximation with a Hubbard-U correction]. The DFT calculations indicate that the spin Hall conductivity is enhanced by the presence of the partially filled f orbitals in Dy and Ho, which suggests a strategy to further strengthen the contribution of the f orbitals to the spin Hall effect by shifting the electron chemical potential.

  10. Seville City Hall Chapter Room ceiling decoration

    Directory of Open Access Journals (Sweden)

    Robador, M. D.

    2010-02-01

    Full Text Available The present article describes a chemical and physical study of the colour, chemical composition and mineral phases of the decorative materials in the Seville City Hall Chapter House ceiling. The findings showed that the inner most layer of material, calcite, was covered with white lead, in turn concealed under a layer of gilded bole. The ceiling underwent re-gilding, also over bole, due in all likelihood to wear on the original gold leaf. In the nineteenth century, the entire ceiling with the exception of the inscriptions was whitewashed with calcite and white lead. Silver was employed on King John I’s sword (coffer 27. Gold leaf was used to adorn the royal attributes: crowns, belts, sceptres, swords and rosary beads. The high reliefs were likewise gilded. The pigments identified on the ceiling adornments included azurite, malachite, vermilion and gas black. A lime and ground dolomite mortar was used throughout.

    El objetivo de este trabajo es el estudio de diferentes aspectos, como el color, la composición química y las fases mineralógicas presentes en los diferentes materiales que forman la ornamentación del techo de la Sala Capitular del Ayuntamiento de Sevilla, mediante métodos físicos y químicos. Nuestros resultados muestran que el dorado fue realizado sobre una capa de bol previamente depositada sobre una lámina de blanco de plomo que cubría un estrato de calcita. Posteriormente, y probablemente debido a alteraciones en el dorado original, el techo fue de nuevo dorado usando una técnica similar. En el siglo XIX, casi todo el techo, excepto las zonas con inscripciones, fue blanqueado usando una mezcla de calcita y blanco de plomo. Se empleó plata para cubrir la espada del rey Juan I (casetón 27. Finísimas láminas de oro se usaron para decorar los atributos reales: coronas, cinturones, cetros, espadas y rosarios. En diferentes partes de la decoración fueron detectados pigmentos como azurita, malaquita, bermellón y

  11. Micro-four-point Probe Hall effect Measurement method

    DEFF Research Database (Denmark)

    Petersen, Dirch Hjorth; Hansen, Ole; Lin, Rong

    2008-01-01

    barriers and with a magnetic field applied normal to the plane of the sheet. Based on this potential, analytical expressions for the measured four-point resistance in presence of a magnetic field are derived for several simple sample geometries. We show how the sheet resistance and Hall effect......We report a new microscale Hall effect measurement method for characterization of semiconductor thin films without need for conventional Hall effect geometries and metal contact pads. We derive the electrostatic potential resulting from current flow in a conductive filamentary sheet with insulating...... contributions may be separated using dual configuration measurements. The method differs from conventional van der Pauw measurements since the probe pins are placed in the interior of the sample region, not just on the perimeter. We experimentally verify the method by micro-four-point probe measurements...

  12. Axisymmetric nonlinear waves and structures in Hall plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Islam, Tanim [Lawrence Livermore National Laboratory, P. O. Box 808, Livermore, California 94551-0808 (United States)

    2012-06-15

    In this paper, a general equation for the evolution of an axisymmetric magnetic field in a Hall plasma is derived, with an integral similar to the Grad-Shafranov equation. Special solutions arising from curvature-whistler drift modes that propagate along the electron drift as a Burger's shock and nonlinear periodic and soliton-like solutions to the generalized Grad-Shafranov integral-are analyzed. We derive analytical and numerical solutions in a classical electron-ion Hall plasma, in which electrons and ions are the only species in the plasmas. Results may then be applied to the following low-ionized astrophysical plasmas: in protostellar disks, in which the ions may be coupled to the motion of gases; and in molecular clouds and protostellar jets, in which the much heavier charged dust in a dusty Hall plasma may be collisionally coupled to the gas.

  13. Maximizing utilization of sport halls during peak hours

    DEFF Research Database (Denmark)

    Iversen, Evald Bundgård; Forsberg, Peter

    the number of participants 7.5 persons higher pr. activity compared to club activities. This implies that clubs during peak hours could include more participants. Another possibility to increase utilization is if the management of sport facilities forced sport clubs and other organisers to adapt......BACKGROUNDDuring peak hours (4.30pm-8pm) demand for timeslots in sport halls in Denmark are high and there are few timeslots available. Further, focus on how public resources are spent most efficient is increasing (Iversen, 2013). This makes it interesting to analyse how utilization could...... be increased during peak hours. DATA AND METHODOLOGYData is collected by observation of activities during two weeks on for example whether halls are used or not; the amount of playing field used; and number of participants (Iversen, 2012). Data on 1.331 activities in 36 sport halls across 4 municipalities have...

  14. Precise quantization of anomalous Hall effect near zero magnetic field

    Science.gov (United States)

    Bestwick, Andrew; Fox, Eli; Kou, Xufeng; Pan, Lei; Wang, Kang; Goldhaber-Gordon, David

    2015-03-01

    The quantum anomalous Hall effect (QAHE) has recently been of great interest due to its recent experimental realization in thin films of Cr-doped (Bi, Sb)2Te3, a ferromagnetic 3D topological insulator. The presence of ferromagnetic exchange breaks time-reversal symmetry, opening a gap in the surface states, but gives rise to dissipationless chiral conduction at the edge of a magnetized film. Ideally, this leads to vanishing longitudinal resistance and Hall resistance quantized to h /e2 , where h is Planck's constant and e is the electron charge, but perfect quantization has so far proved elusive. Here, we study the QAHE in the limit of zero applied magnetic field, and measure Hall resistance quantized to within one part per 10,000. Deviation from quantization is due primarily to thermally activated carriers, which can be nearly eliminated through adiabatic demagnetization cooling. This result demonstrates an important step toward dissipationless electron transport in technologically relevant conditions.

  15. Crossover between spin swapping and Hall effect in disordered systems

    KAUST Repository

    Saidaoui, Hamed Ben Mohamed

    2015-07-16

    We theoretically study the crossover between spin Hall effect and spin swapping, a recently predicted phenomenon that consists of the interchange between the current flow and its spin polarization directions [M. B. Lifshits and M. I. Dyakonov, Phys. Rev. Lett. 103, 186601 (2009)]. Using a tight-binding model with spin-orbit coupled disorder, spin Hall effect, spin relaxation, and spin swapping are treated on equal footing. We demonstrate that spin swapping and spin Hall effect present very different dependencies as a function of the spin-orbit coupling and disorder strengths and confirm that the former exceeds the latter in the parameter range considered. Three setups are proposed for the experimental observation of the spin swapping effect.

  16. Quantum Hall fluids in the presence of topological defects

    CERN Document Server

    Iacomino, Patrizia; Naddeo, Adele

    2013-01-01

    We review our recent results on the physics of quantum Hall fluids at Jain and non conventional fillings within a general field theoretic framework. We focus on a peculiar conformal field theory (CFT), the one obtained by means of the m-reduction technique, and stress its power in describing strongly correlated low dimensional condensed matter systems in the presence of localized impurities or topological defects. By exploiting the notion of Morita equivalence for field theories on noncommutative two-tori and choosing rational values of the noncommutativity parameter, we find a general one-to-one correspondence between the m-reduced conformal field theory describing the quantum Hall fluid and an Abelian noncommutative field theory. As an example of application of the formalism, we study a quantum Hall bilayer at nonconventional fillings in the presence of a localized topological defect and briefly recall its boundary state structure corresponding to two different boundary conditions, the periodic as well as t...

  17. Novel Hall sensors developed for magnetic field imaging systems

    Science.gov (United States)

    Cambel, Vladimír; Karapetrov, Goran; Novosad, Valentyn; Bartolomé, Elena; Gregušová, Dagmar; Fedor, Ján; Kúdela, Robert; Šoltýs, Ján

    2007-09-01

    We report here on the fabrication and application of novel planar Hall sensors based on shallow InGaP/AlGaAs/GaAs heterostructure with a two-dimensional electron gas (2DEG) as an active layer. The sensors are developed for two kinds of experiments. In the first one, magnetic samples are placed directly on the Hall sensor. Room temperature experiments of permalloy objects evaporated onto the sensor are presented. In the second experiment, the sensor scans close over a multigranular superconducting sample prepared on a YBCO thin film. Large-area and high-resolution scanning experiments were performed at 4.2 K with the Hall probe scanning system in a liquid helium flow cryostat.

  18. Graphene and the universality of the quantum Hall effect

    DEFF Research Database (Denmark)

    Tzalenchuk, A.; Janssen, T. J.B.M.; Kazakova, O.

    2013-01-01

    The quantum Hall effect allows the standard for resistance to be defined in terms of the elementary charge and Planck's constant alone. The effect comprises the quantization of the Hall resistance in two-dimensional electron systems in rational fractions of RK=h/e2=25812.8074434(84) Ω (Mohr P. J....... et al., Rev. Mod. Phys., 84 (2012) 1527), the resistance quantum. Despite 30 years of research into the quantum Hall effect, the level of precision necessary for metrology, a few parts per billion, has been achieved only in silicon and III-V heterostructure devices. In this lecture we show...... that graphene - a single layer of carbon atoms - beats these well-established semiconductor materials as the system of choice for the realisation of the quantum resistance standard. Here we shall briefly describe graphene technology, discuss the structure and electronic properties of graphene, including...

  19. Collective edge modes in fractional quantum Hall systems

    Science.gov (United States)

    Nguyen, Hoang K.; Joglekar, Yogesh N.; Murthy, Ganpathy

    2004-07-01

    Over the past few years one of us (Murthy) in collaboration with Shankar has developed an extended Hamiltonian formalism capable of describing the ground-state and low-energy excitations in the fractional quantum Hall regime. The Hamiltonian, expressed in terms of composite fermion operators, incorporates all the nonperturbative features of the fractional Hall regime, so that conventional many-body approximations such as Hartree-Fock and time-dependent Hartree-Fock are applicable. We apply this formalism to develop a microscopic theory of the collective edge modes in fractional quantum Hall regime. We present the results for edge mode dispersions at principal filling factors ν=1/3 , 1/5 , and 2/5 for systems with unreconstructed edges. The primary advantage of the method is that one works in the thermodynamic limit right from the beginning, thus avoiding the finite-size effects which ultimately limit exact diagonalization studies.

  20. Metal-to-insulator switching in quantum anomalous Hall states

    Science.gov (United States)

    Pan, Lei; Kou, Xufeng; Wang, Jing; Fan, Yabin; Choi, Eun Sang; Shao, Qiming; Zhang, Shou Cheng; Wang, Kang Lung

    Quantum anomalous Hall effect (QAHE) was recently achieved in magnetic topological insulator films as a form of dissipationless transport without external magnetic field. However, the universal phase diagram of QAHE and its relation with quantum Hall effect (QHE) remain to be investigated. Here, we report the experimental observation of the giant longitudinal resistance peak and zero Hall conductance plateau at the coercive field in the six quintuple-layer (Cr0.12Bi0.26Sb0.62)2 Te3 film, and demonstrate the metal-to-insulator switching between two opposite QAHE plateau states up to 0.3 K. The universal QAHE phase diagram is further confirmed through the angle-dependent measurements. Our results address that the quantum phase transitions in both QAHE and QHE regimes are in the same universality class, yet the microscopic details are different.

  1. Quantitative Analysis of Spin Hall Effect in Nanostructures

    Directory of Open Access Journals (Sweden)

    S. Katiyal

    2012-07-01

    Full Text Available Spin transport in nano structured devices depends on interfaceresistance, electrode resistance, Spin polarization and Spindiffusion length. Spin Hall Effect (SHE, caused by Spin–orbitscattering in nonmagnetic conductors, gives rise to theconversion between Spin and charge currents in a non localdevice. Recently, SHE has been observed using non local Spininjection in metal-based nanostructured devices, which pavesthe way for future Spin electronic applications. In presentwork we have theoretically analyzed the SHE phenomenabased on experimental results obtained till date. We have usedthe Hamiltonian of two dimensional electron systems withRashba Spin-orbit coupling. We undertake the quantitativeanalysis of Spin Hall Effect in low dimensional materialsusing Spin dynamical equations and Spin Hall conductivity.

  2. Thermal Hall Effect of Spin Excitations in a Kagome Magnet.

    Science.gov (United States)

    Hirschberger, Max; Chisnell, Robin; Lee, Young S; Ong, N P

    2015-09-04

    At low temperatures, the thermal conductivity of spin excitations in a magnetic insulator can exceed that of phonons. However, because they are charge neutral, the spin waves are not expected to display a thermal Hall effect. However, in the kagome lattice, theory predicts that the Berry curvature leads to a thermal Hall conductivity κ(xy). Here we report observation of a large κ(xy) in the kagome magnet Cu(1-3, bdc) which orders magnetically at 1.8 K. The observed κ(xy) undergoes a remarkable sign reversal with changes in temperature or magnetic field, associated with sign alternation of the Chern flux between magnon bands. The close correlation between κ(xy) and κ(xx) firmly precludes a phonon origin for the thermal Hall effect.

  3. The onset of MHD nanofluid convection with Hall current effect

    Science.gov (United States)

    Yadav, Dhananjay; Lee, Jinho

    2015-08-01

    In this paper, the combined effects of Hall current and magnetic field on the onset of convection in an electrically conducting nanofluid layer heated from below is investigated. A physically more realistic boundary condition on the nanoparticle volume fraction is taken i.e. the nanoparticle flux is assumed to be zero rather than prescribing a nanoparticle volume fraction on the rigid impermeable boundaries. The employed model incorporates the effects of Brownian motion and thermophoresis. The resulting eigenvalue problem is solved using the Galerkin method. The results obtained during the analysis are presented graphically for an alumina-water nanofluid. It is observed that the effect of smaller values of the Hall current parameter and the nanoparticle parameters accelerate the onset of convection, while larger values of the Hall current parameter (≥ 15) have no effect on the system stabilities.

  4. The complete set of Casimirs in Hall-magnetohydrodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Kawazura, Yohei [Graduate School of Frontier Sciences, University of Tokyo Kashiwa, Chiba 277-8561 (Japan); Hameiri, Eliezer [Courant Institute of Mathematical Sciences, New York University, New York, New York 10012 (United States)

    2012-08-15

    A procedure for determining all the Casimir constants of motion in magnetohydrodynamics (MHD) [E. Hameiri, Phys. Plasmas 11, 3423 (2004)] is extended to Hall-MHD. We obtain and solve differential equations for the variational derivatives of all the Casimirs, which must be satisfied for any dynamically accessible motion in Hall-MHD. In an extension of the more commonly considered Hall-MHD model, we also include the electron fluid entropy. The most interesting case for plasma confinement, which is usually true for axisymmetric configurations but desirable in general, is when both the magnetic field and the ion velocity field form the two separate families of nested toroidal surfaces. The Casimirs are then three functionals for each surface, involving the fluxes of certain vector fields and the number of particles contained in each. We also determine a family of independent Casimirs in a general configuration.

  5. Maximizing utilization of sport halls during peak hours

    DEFF Research Database (Denmark)

    Iversen, Evald Bundgård; Forsberg, Peter

    be increased during peak hours. DATA AND METHODOLOGYData is collected by observation of activities during two weeks on for example whether halls are used or not; the amount of playing field used; and number of participants (Iversen, 2012). Data on 1.331 activities in 36 sport halls across 4 municipalities have...... been collected. RESULTS The number of participants per activity is higher during peak hours, which is expected when demand is high. However, the usage of sport floor only differs slightly between peak and low hours. Both during peak and low hours on average 80-100 per cent of floor space is used......BACKGROUNDDuring peak hours (4.30pm-8pm) demand for timeslots in sport halls in Denmark are high and there are few timeslots available. Further, focus on how public resources are spent most efficient is increasing (Iversen, 2013). This makes it interesting to analyse how utilization could...

  6. Spontaneous chiral symmetry breaking of Hall magnetohydrodynamic turbulence.

    Science.gov (United States)

    Meyrand, Romain; Galtier, Sébastien

    2012-11-01

    Hall magnetohydrodynamics (MHD) is investigated through three-dimensional direct numerical simulations. We show that the Hall effect induces a spontaneous chiral symmetry breaking of the turbulent dynamics. The normalized magnetic polarization is introduced to separate the right- (R) and left-handed (L) fluctuations. A classical k(-7/3) spectrum is found at small scales for R magnetic fluctuations which corresponds to the electron MHD prediction. A spectrum compatible with k(-11/3) is obtained at large-scales for the L magnetic fluctuations; we call this regime the ion MHD. These results are explained heuristically by rewriting the Hall MHD equations in a succinct vortex dynamical form. Applications to solar wind turbulence are discussed.

  7. D0 Detector Collision Hall Oxygen Deficiancy Hazard Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Wu, J.; /Fermilab

    1992-08-06

    EN-258, D0 Platform ODH Analysts. provided the oxygen deficiency hazard analysts for the D0 detector in the Assembly Hall. This note covers the same analysis. but revised for the Collision Hall. Liquid cryogens. released and warming to atmosphere conditions, expand to, on average, seven hundred times their liquid volume, and displace vital atmospheric oxygen. An oxygen deficiency hazard analysis assesses the increased risk to personnel in areas containing cryogenic systems. The D0 detector Collision Hall ODH analysis has been approached five different ways using established methods. If the low beta quad magnets are powered, and the exhaust rate is below 4220 scfm, the area is ODH class 1. In any other case, the analysis shows the area to be ODH class 0 as equipped (with ventilation fans) and requiring no special safety provisions. System designers have provided for a reduced oxygen level detection and warning system as well as emergency procedures to address fault conditions.

  8. The complete set of Casimirs in Hall-magnetohydrodynamics

    Science.gov (United States)

    Kawazura, Yohei; Hameiri, Eliezer

    2012-08-01

    A procedure for determining all the Casimir constants of motion in magnetohydrodynamics (MHD) [E. Hameiri, Phys. Plasmas 11, 3423 (2004)] is extended to Hall-MHD. We obtain and solve differential equations for the variational derivatives of all the Casimirs, which must be satisfied for any dynamically accessible motion in Hall-MHD. In an extension of the more commonly considered Hall-MHD model, we also include the electron fluid entropy. The most interesting case for plasma confinement, which is usually true for axisymmetric configurations but desirable in general, is when both the magnetic field and the ion velocity field form the two separate families of nested toroidal surfaces. The Casimirs are then three functionals for each surface, involving the fluxes of certain vector fields and the number of particles contained in each. We also determine a family of independent Casimirs in a general configuration.

  9. Risk factors for meningococcal disease in university halls of residence.

    Science.gov (United States)

    Nelson, S. J.; Charlett, A.; Orr, H. J.; Barker, R. M.; Neal, K. R.; Taylor, C.; Monk, P. N.; Evans, M. R.; Stuart, J. M.

    2001-01-01

    A retrospective ecological study was undertaken to identify social and environmental factors associated with increased incidence of meningococcal disease in university halls of residence. A standardized questionnaire was sent to UK universities and colleges of higher education outside London, for distribution to halls containing at least 50 students. Incidence rate ratios of invasive meningococcal disease were obtained for a range of social and environmental variables. Multi-variable Poisson regression analysis identified 3 factors as having a strong association: a high proportion of first year undergraduate residents (P = 0.0008), decreasing smokiness of the hall bar (P Universities should continue to promote awareness of meningococcal disease, encourage vaccination of first year students against serogroup C disease, and where appropriate, take measures to reduce overcrowding. PMID:11349971

  10. Composed planar Hall effect sensors with dual-mode operation

    Science.gov (United States)

    Mor, Vladislav; Roy, Debangsu; Schultz, Moty; Klein, Lior

    2016-02-01

    We present a composed planar Hall effect sensor with two modes of operation: (a) an ON mode where the composed sensor responds to magnetic field excitations similarly to the response of a regular planar Hall effect sensor, and (b) an OFF mode where the response is negligible. The composed planar Hall effect sensor switches from the OFF mode to the ON mode when it is exposed to a magnetic field which exceeds a certain threshold determined by the sensor design. The features of this sensor make it useful as a switch triggered by magnetic field and as a sensing device with memory, as its mode of operation indicates exposure to a magnetic field larger than a certain threshold without the need to be activated during the exposure itself.

  11. Nonlinear transport of graphene in the quantum Hall regime

    Science.gov (United States)

    Tian, Shibing; Wang, Pengjie; Liu, Xin; Zhu, Junbo; Fu, Hailong; Taniguchi, Takashi; Watanabe, Kenji; Chen, Jian-Hao; Lin, Xi

    2017-03-01

    We have studied the breakdown of the integer quantum Hall (QH) effect with fully broken symmetry, in an ultra-high mobility graphene device sandwiched between two single crystal hexagonal boron nitride substrates. The evolution and stabilities of the QH states are studied quantitatively through the nonlinear transport with dc Hall voltage bias. The mechanism of the QH breakdown in graphene and the movement of the Fermi energy with the electrical Hall field are discussed. This is the first study in which the stabilities of fully symmetry broken QH states are probed all together. Our results raise the possibility that the ν = ±6 states might be a better target for the quantum resistance standard.

  12. μHall chip for sensitive detection of bacteria.

    Science.gov (United States)

    Issadore, David; Chung, Hyun Jung; Chung, Jaehoon; Budin, Ghyslain; Weissleder, Ralph; Lee, Hakho

    2013-09-01

    Sensitive, rapid and phenotype-specific enumeration of pathogens is essential for the diagnosis of infectious disease, monitoring of food chains, and for defense against bioterrorism. Microbiological culture and genotyping, techniques that sensitively and selectively detect bacteria in laboratory settings, have limited application in clinical environments due to high cost, slow response times, and the need for specially trained staff and laboratory infrastructure. To address these challenges, we developed a microfluidic chip-based micro-HallHall) platform capable of measuring single, magnetically tagged bacteria directly in clinical specimens with minimal sample processing. We demonstrated the clinical utility of the μHall chip by enumerating Gram-positive bacteria. The overall detection limit of the system was similar to that of culture tests (~10 bacteria), but the assay time was 50-times faster. This low-cost, single-cell analytical technique is especially well-suited to diagnose infectious diseases in resource-limited clinical settings.

  13. Overview of NASA Iodine Hall Thruster Propulsion System Development

    Science.gov (United States)

    Smith, Timothy D.; Kamhawi, Hani; Hickman, Tyler; Haag, Thomas; Dankanich, John; Polzin, Kurt; Byrne, Lawrence; Szabo, James

    2016-01-01

    NASA is continuing to invest in advancing Hall thruster technologies for implementation in commercial and government missions. The most recent focus has been on increasing the power level for large-scale exploration applications. However, there has also been a similar push to examine applications of electric propulsion for small spacecraft in the range of 300 kg or less. There have been several recent iodine Hall propulsion system development activities performed by the team of the NASA Glenn Research Center, the NASA Marshall Space Flight Center, and Busek Co. Inc. In particular, the work focused on qualification of the Busek 200-W BHT-200-I and development of the 600-W BHT-600-I systems. This paper discusses the current status of iodine Hall propulsion system developments along with supporting technology development efforts.

  14. Hall coefficient of insulating n-type CdSe

    Energy Technology Data Exchange (ETDEWEB)

    Roy, A.; Levy, M.; Guo, X.M.; Sarachik, M.P.; Ledesma, R.; Isaacs, L.L.

    1989-05-15

    We report measurements of the conductivity and Hall coefficient of insulating n-type CdSe with dopant concentrations near the critical concentration for the metal-insulator transition. In the temperature range 1.2--4.2 K, where the resistivity is consistent with variable-range hopping, the Hall coefficient is finite and observable and follows an analogous temperature dependence, R/sub H//similar to/exp(K/sub H/(T/sub 0//T)/sup n/). We find n<1, so that the observed Hall coefficient is not due to carriers activated to extended states; the data are consistent instead with an exponent n = 1/4 or 1/2. We compare this result with previous experiments and with current theory.

  15. Non-Abelian 3d Bosonization and Quantum Hall States

    CERN Document Server

    Radicevic, Djordje; Turner, Carl

    2016-01-01

    Bosonization dualities relate two different Chern-Simons-matter theories, with bosonic matter on one side replaced by fermionic matter on the other. We first describe a more general class of non-Abelian bosonization dualities. We then explore the non-relativistic physics of these theories in the quantum Hall regime. The bosonic theory lies in a condensed phase and admits vortices which are known to form a non-Abelian quantum Hall state. We ask how this same physics arises in the fermionic theory. We find that a condensed boson corresponds to a fully filled Landau level of fermions, while bosonic vortices map to fermionic holes. We confirm that the ground state of the two theories is indeed described by the same quantum Hall wavefunction.

  16. Carl Gustav Jung and Granville Stanley Hall on Religious Experience.

    Science.gov (United States)

    Kim, Chae Young

    2016-08-01

    Granville Stanley Hall (1844-1924) with William James (1842-1910) is the key founder of psychology of religion movement and the first American experimental or genetic psychologist, and Carl Gustav Jung (1875-1961) is the founder of the analytical psychology concerned sympathetically about the religious dimension rooted in the human subject. Their fundamental works are mutually connected. Among other things, both Hall and Jung were deeply interested in how the study of religious experience is indispensable for the depth understanding of human subject. Nevertheless, except for the slight indication, this common interest between them has not yet been examined in academic research paper. So this paper aims to articulate preliminary evidence of affinities focusing on the locus and its function of the inner deep psychic dimension as the religious in the work of Hall and Jung.

  17. The spin Hall effect of light in moving medium

    Science.gov (United States)

    Li, Hehe; Li, Xinzhong; Wang, Jingge

    2017-01-01

    In this paper, we investigate the spin Hall effect of light in moving inhomogeneous medium using the Gordon metric and the Maxwell’s equations in the gravitational field. Light experiences a moving medium as a gravitational field by means of the Gordon metric. It is shown that the spin Hall effect of light is modified by the motion of medium, and the deflection of the ray trajectory is dependent on the polarization and the motion of the medium. It is interesting that there is no coupling of the spin angular momentum of light and the effective gravitational field when the medium is moving along the direction of the gradient ∇n(r). The results provide a potential method for controlling the spin Hall effect of light in medium.

  18. A Simulation Study of Hall Effect on Double Tearing Modes

    Institute of Scientific and Technical Information of China (English)

    ZHANG Chenglong; MA Zhiwei; DONG Jiaqi

    2008-01-01

    A Hall magnetohydrodynamics (MHD) simulation is carried out to study the dy-namic process of double tearing mode. The results indicated that the growth rates in the earlier nonlinear and transition phases agree with the previous results. With further development of reconnection, the current sheet thickness is much smaller than the ion inertia length, which leads to a strong influence of the Hall effects. As a result, the reconnection in the late nonlinear phase exhibits an explosive nature with a time scale nearly independent of resistivity. A localized and severely intensified current density is observed and the maximum kinetic energy is over one order of magnitude higher in Hall MHD than that in resistive MHD.

  19. Quantum anomalous Hall effect in magnetic insulator heterostructure.

    Science.gov (United States)

    Xu, Gang; Wang, Jing; Felser, Claudia; Qi, Xiao-Liang; Zhang, Shou-Cheng

    2015-03-11

    On the basis of ab initio calculations, we predict that a monolayer of Cr-doped (Bi,Sb)2Te3 and GdI2 heterostructure is a quantum anomalous Hall insulator with a nontrivial band gap up to 38 meV. The principle behind our prediction is that the band inversion between two topologically trivial ferromagnetic insulators can result in a nonzero Chern number, which offers a better way to realize the quantum anomalous Hall state without random magnetic doping. In addition, a simple effective model is presented to describe the basic mechanism of spin polarized band inversion in this system. Moreover, we predict that 3D quantum anomalous Hall insulator could be realized in (Bi2/3Cr1/3)2Te3 /GdI2 superlattice.

  20. Plasma Diagnostic and Performance of a Permanent Magnet Hall Thruster

    CERN Document Server

    Ferreira, J L; Rego, I D S; Ferreira, I S; Ferreira, Jose Leonardo; Souza, Joao Henrique Campos De; Rego, Israel Da Silveira; Ferreira, Ivan Soares

    2004-01-01

    Electric propulsion is now a sucessfull method for primary propulsion of deep space long duration missions and for geosyncronous satellite attitude control. Closed Drift Plasma Thruster, so called Hall Thruster or SPT (stationary plasma thruster) were primarily conceived in USSR (the ancient Soviet Union) and now it is been developed by space agencies, space research institutes and industries in several countries such as France, USA, Israel, Russian Federation and Brazil. In this work, we show plasma characteristics and performance of a Hall Thruster designed with an innovative concept which uses an array of permanent magnets, instead of an eletromagnet, to produce a radial magnetic field inside its cylindrical plasma drift channel. Within this new concept, we expect to develop a Hall Thruster within power consuption that will scale up to small and medium size satellites. A plasma density and temperature space profiles inside and outside the thruster channel will be shown. Space plasma potential, ion temperat...