A Residential Paradox?: Residence Hall Attributes and College Student Outcomes
Bronkema, Ryan; Bowman, Nicholas A.
2017-01-01
The researchers of this brief observed that few environments have the potential to shape the outcomes of college students as much as residence halls. As a result, residence halls have the capacity to foster a strong sense of community as well as other important outcomes such as college satisfaction and academic achievement. However, given the high…
The Marketing of Residence Halls: A Question of Positioning.
Parker, R. Stephen; And Others
1996-01-01
A survey of 343 college residence hall directors revealed percentages of private and public institutions offering different amenities, main selling points in promotional brochures, and the most common resident complaints. Results were compared with those of a resident survey concerning the importance of various housing attributes. Implications for…
Involving Students in Residence Halls in Hong Kong
Ting, S. Raymond; Chan, Rebecca; Lee, Esther
2016-01-01
This article reports a study based on A. W. Astin's (1984) involvement theory applied in residence halls at a public university in Hong Kong, China. The resident students who were involved as participants or student leaders in this study were found to be better developed in terms of leadership, career development, multicultural experience,…
The Role of Social Influence on How Residence Hall Inhabitants Respond to Fire Alarms
Leytem, Michael; Stark, Emily
2016-01-01
College resident halls pose a threat for a catastrophic event in the case of fire, but little research has examined potential influences on students' responses to fire alarms, particularly the role of social influence in affecting their behaviors. In the current study, residence hall inhabitants reported their knowledge about fire safety, their…
"Are You as Hard as 50 Cent? Negotiating Race and Masculinity in the Residence Halls
Jaggers, Dametraus; Iverson, Susan V.
2012-01-01
In a qualitative study of Black undergraduate men at a predominantly White university in the Midwest, participants shared their experiences in residence halls, including roommate conflicts, interracial tensions, and disagreements with residence hall staff. This article focuses on Black male undergraduates' negotiation of racialized conceptions of…
The Development of a Tutor Programme in a University Hall of Residence--A Case Study.
Beasley, V. J.
The tutor system within a university hall of residence at Flinders University of South Australia and a method of inquiry used to study the system are examined. Interviews with residence hall tutors revealed four concerns: the need for guidelines, the nature of academic tutoring, pastoral care and its implications, and communication channels within…
"Are You as Hard as 50 Cent?" Negotiating Race and Masculinity in the Residence Halls
Jaggers, Dametraus; Iverson, Susan V.
2012-01-01
In a qualitative study of Black undergraduate men at a predominantly White university in the Midwest, participants shared their experiences in residence halls, including roommate conflicts, interracial tensions, and disagreements with residence hall staff. This article focuses on Black male undergraduates' negotiation of racialized conceptions of…
Alcohol Trajectories over Three Years in a Swedish Residence Hall Student Population
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Henriettae Ståhlbrandt
2010-03-01
Full Text Available Although it is known that college students have a high alcohol consumption, less is known about the long-term drinking trajectories amongst college students and, in particular, students living in residence halls, known to be high-risk drinkers. Over four consecutive years, the drinking habits of 556 Swedish residence hall students were analyzed. The main instruments for measuring outcome were AUDIT (Alcohol Use Identification Disorders Test, SIP (Short Index of Problems and eBAC (estimated Blood Alcohol Concentration. The drinking trajectories among Swedish residence hall students showed stable and decreasing drinking patterns, with age and gender being predictors of group membership.
Boekeloo, Bradley O.; Bush, Elizabeth N.; Novik, Melinda G.
2009-01-01
Objective: The authors examined the secondhand effects among college freshmen of others' alcohol use and related student characteristics, and perceptions about residence hallmates. Participants: The authors surveyed 509 incoming freshmen residing in predominantly freshman residence halls. Methods: The authors administered a Web-based survey 2…
Style of Life and Student Personnel Policy in College Residence Halls
White, Julie E.
1969-01-01
Doctoral dissertation, Dimensions of Conformity and Evasion in Residence Halls for University Women: A Sociological Analysis of Normative Behavior in a Large-Scale Social Organization, 1962, University of Illinois, Urbana.
Resident physicians in Mexico: tradition or humiliation
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Donovan Casas Patiño
2013-08-01
Full Text Available Mexico has a great history and tradition in relation to the training of resident physicians, but what we find behind this process?, Power relations implied and not implied, unnoticed or ignored for convenience by the academic and health institutions, with the aggravation of forgetting its commitment to the training of men and women "professionals" and limited to meet another indicator of "human resources for health." The resident physician in academic and scientific training is immersed in this dehumanized maelstrom and ends up becoming a character for the domain of knowledge as power, forgetting that his act and its rationale lies in the principle of "primum non nocere" to that we would add: nor your person, nor your fellowman, much less whom you have the moral, ethical and civic responsibility to convey some of your knowledge and your experience, that is, part of your essence”.
What Residence Hall Staff Need to Know about Dealing with Death.
Jacobs, Bonita; Towns, James E.
1984-01-01
Emphasizes the responsibility for residence hall staff to understand the grief process. An adaptation of Kubler-Ross's stages of death has produced helpful techniques for successfully accepting the death. Through understanding these principles, staff can become aware of the grief process and can assist residents. (JAC)
McCarty, Shane M.; Mullins, Taris G.; Geller, E. Scott; Shushok, Frank, Jr.
2013-01-01
A professor and a group of student leaders initiated the Actively Caring for People (AC4P) Movement to establish a more civil, compassionate, and inclusive culture by inspiring intentional acts of kindness. This article explores the AC4P Movement in a first-year residence hall at Virginia Tech and a second-year residence hall at University of…
Students' Sense of Community in Residence Halls, Social Integration, and First-Year Persistence.
Berger, Joseph B.
1997-01-01
Used concepts from community psychology literature to elaborate a revised version of Tinto's model of individual student departure. Employed a longitudinal analysis of 718 college students. Results indicate that students' sense of community in their residence halls was a source of social integration and a precursor to student departure decisions.…
Students' Perceptions of the Residence Hall Living Environment at Kuwait University
Al Kandari, Nabila
2007-01-01
The purpose of this study is to explore students' perceptions of the residence hall living environment at Kuwait University. The researcher developed a questionnaire for this purpose that included 36 items. The sample of the study consisted of 191 residential students, of whom 98 were male and 93 were female. The research findings indicated that:…
Seabourg, Deborah; And Others
At the beginning of the 1973-74 academic year alcohol usage was officially permitted for the first time in residence halls at the Twin Cities Campus of the University of Minnesota. To determine residents' perceptions of the effects of the change in drinking policy, interviews were conducted with 49 current dormitory residents, who had also lived…
Amber, Khuram Pervez; Aslam, Muhammad Waqar
2018-03-01
Student residence halls occupy 26% of the total area of a typical university campus in the UK and are directly responsible for 24% of university's annual CO2 emissions. Based on five years measured data, this paper aims to investigate the energy-related environmental and economic performance of electrically heated residence halls in which space heating is provided by two different types of electric heaters, that is, panel heater (PHT) and storage heater (SHT). Secondly, using statistical and machine learning methods, the paper attempts to investigate the relationship between daily electricity consumption and five factors (ambient temperature, solar radiation, relative humidity, wind speed and type of day). Data analysis revealed that electricity consumption of both halls is mainly driven by ambient temperature only, whereas SHT residence has 39% higher annual electricity bill and emits 70% higher CO2 emissions on a per square metre basis compared to the PHT residence hall.
The effect of hand hygiene on illness rate among students in university residence halls.
White, Cindy; Kolble, Robin; Carlson, Rebecca; Lipson, Natasha; Dolan, Mike; Ali, Yusuf; Cline, Mojee
2003-10-01
Several studies have indicated a connection between hand sanitization and infection control in numerous settings such as extended care facilities, schools, and hospitals. The purpose of this study was to assess the effectiveness of both a hand-hygiene message campaign and the use of an alcohol gel hand sanitizer in decreasing the incidence of upper-respiratory illness among students living in university residence halls. This study involved a total of 430 students recruited from 4 residence halls during the fall semester at the University of Colorado at the Boulder campus. Dormitories were paired into control and product groups. In the product groups, alcohol gel hand-sanitizer dispensers were installed in every room, bathroom, and dining hall. The data were statistically analyzed for the differences between product and control groups in reported symptoms, illness rates, and absenteeism from classes. The overall increase in hand-hygiene behavior and reduction in symptoms, illness rates, and absenteeism between the product group and control group was statistically significant. Reductions in upper respiratory-illness symptoms ranged from 14.8% to 39.9%. Total improvement in illness rate was 20%. The product group had 43% less missed school/work days. Hand-hygiene practices were improved with increased frequency of handwashing through increasing awareness of the importance of hand hygiene, and the use of alcohol gel hand sanitizer in university dormitories. This resulted in fewer upper respiratory-illness symptoms, lower illness rates, and lower absenteeism.
Assimilating Traditional Healing Into Preventive Medicine Residency Curriculum.
Kesler, Denece O; Hopkins, L Olivia; Torres, Eliseo; Prasad, Arti
2015-11-01
Comprehensive cultural competency includes knowledge and awareness of culturally based healing and wellness practices. Healthcare providers should be aware of the individual patient's beliefs, culture, and use of culturally based health practices because patients may adopt such practices for general wellness or as adjunct therapies without the benefit of discussion with their healthcare provider. This article describes the culturally based traditional healing curriculum that has been implemented in the University of New Mexico Public Health and General Preventive Medicine Residency Program in order to fulfill this knowledge necessity. Curricular elements were added in a stepwise manner starting in 2011, with the full content as described implemented starting in 2013. Data were collected annually with evaluation of the full curriculum occurring in 2015. New Mexico has a diverse population base that includes predominantly Hispanic and Native American cultures, making the inclusion of curriculum regarding traditional healing practices very pertinent. Residents at the University of New Mexico were educated through several curricular components about topics such as Curanderismo, the art of Mexican Folk Healing. An innovative approach was used, with a compendium of training methods that included learning directly from traditional healers and participation in healing practices. The incorporation of this residency curriculum resulted in a means to produce physicians well trained in approaching patient care and population health with knowledge of culturally based health practices in order to facilitate healthy patients and communities. Copyright © 2015 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.
White, Cindy; Kolble, Robin; Carlson, Rebecca; Lipson, Natasha
2005-01-01
Hand hygiene is a key element in preventing the transmission of cold and flu viruses. The authors conducted an experimental-control design study in 4 campus residence halls to determine whether a message campaign about hand hygiene and the availability of gel hand sanitizer could decrease cold and flu illness and school and work absenteeism. Their…
Evacuation Simulation in Kalayaan Residence Hall, up Diliman Using Gama Simulation Software
Claridades, A. R. C.; Villanueva, J. K. S.; Macatulad, E. G.
2016-09-01
Agent-Based Modeling (ABM) has recently been adopted in some studies for the modelling of events as a dynamic system given a set of events and parameters. In principle, ABM employs individual agents with assigned attributes and behaviors and simulates their behavior around their environment and interaction with other agents. This can be a useful tool in both micro and macroscale-applications. In this study, a model initially created and applied to an academic building was implemented in a dormitory. In particular, this research integrates three-dimensional Geographic Information System (GIS) with GAMA as the multi-agent based evacuation simulation and is implemented in Kalayaan Residence Hall. A three-dimensional GIS model is created based on the floor plans and demographic data of the dorm, including respective pathways as networks, rooms, floors, exits and appropriate attributes. This model is then re-implemented in GAMA. Different states of the agents and their effect on their evacuation time were then observed. GAMA simulation with varying path width was also implemented. It has been found out that compared to their original states, panic, eating and studying will hasten evacuation, and on the other hand, sleeping and being on the bathrooms will be impedances. It is also concluded that evacuation time will be halved when path widths are doubled, however it is recommended for further studies for pathways to be modeled as spaces instead of lines. A more scientific basis for predicting agent behavior in these states is also recommended for more realistic results.
Residents' Perceptions of Property Rating in a Traditional African City
African Journals Online (AJOL)
The success of any revenue generation drive by government depends on the support shown by an area's residents. This in turn depends on the latter's perceptions of the revenue. This study examines the influence of residents' perceptions of a property tax in the different residential districts of Ogbomoso, Oyo State, Nigeria.
Using the Leaderless Group Discussion Technique for the Selection of Residence Hall Counselors
Banta, Trudy W.; McCormick, Jane E.
1969-01-01
Describes successful effort to involve head residents in selection responsibilities. Discusses use of Record of Previous Leadership Experience, behavior ratings adapted from Interview and LGD Rating Scale (T. W. Banta) recommendation from head resident as selection criteria. (CJ)
Kurnia Widianti, An-nisaa; Bambang Studyanto, Anung
2018-03-01
Kertha Gosa Klungkung Court Hall in Bali is one of the relics of the cultural heritage of The Kingdom of Bali which is a part of the Klungkung Castle. The existence of Kertha Gosa Architecture Hall as one of the relics of cultural heritage holds historical values, especially Bali traditional values. Indonesia is a country which has the rich culture heritage history, especially on historical buildings. This research seeks for a redenomination to solve problems being faced recently, namely the lack of activities to conserve a historic building as an asset of the country and source of knowledge in education. Listed in Law Number 11 of 2010 the conservation has some criteria, such as : 1.it has 50 years or more; represents the period of a certain style lat least 50 years; has special meaning for the history, science, education, religion, and culture or cultural value as a nation’s personality. The procedure to conduct this research uses a descriptive method by doing observation, interviews, taking some pictures, official documents or personal and other data that have a relevance to the research related to object to describing the condition of the building systematically, factual and actual. Consideration of the selection of objects is based on research by looking at the criteria of architectural, historical and symbolic criteria. Kertha Gosa Hall classic has been there for 395 years was built with zoning system called Sanga Mandala or similar to a chess board using natural materials such as eben wood, and padas rocks which make it authentic and possesses characteristic values of patriotism expression. During the kingdom of Kertha Gosa, Court Hall was like a court nowadays, but people still trust the constructive value of Hindu religion and culture as a product of thinking and live experience.
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Ozge Yavuz Sari
2015-04-01
Full Text Available AIM: Sleep disorders are remarkable public health problems as they adversely affect physical, mental and social health and may cause accidents and decline in academic performance and labor productivity. Aim of the study is assessing sleep quality and determining some factors affecting sleep quality in the students living in the residence hall of a university. METHOD: It is a cross sectional study conducted with 277 students, 180 of whom are female. Data were collected via a questionnaire including Pittsburgh Sleep Quality Index (PSQI, Epworth Sleepiness Scale (ESS and socio-demographic characteristics query. RESULTS: According to PSQI, 41.1% of students have bad sleep quality. Sleep quality of male students and students who are overweight/obese or living in more crowded rooms in the hall of residence is worse than other students and #8217;. Prevalence of bad sleep quality is higher in medication users, participants thinking that they have problems in sleeping or falling asleep and had stressful experience in the last month. The differences between groups were statistically significant. In logistic regression analyzes, using medication (OR=2.54, having problems in sleep (OR=12.75, having problems in falling asleep (OR=8.83 and bad experiences in the last month (OR=2.66 have effects on sleep quality. CONCLUSIONS: Interventions about sleep disorders are important due to their preventable characteristics. Developing healthy life habits, improving physical conditions and coping with stress will be effective on preventing and treating sleep disorders. [TAF Prev Med Bull 2015; 14(2.000: 93-100
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Marta Kawa
2014-09-01
Full Text Available The paper presents the factors determining the choice of traditional and regional products by Podkarpacie residents. The surveyed consumers found the quality as the most important trait that encourages the purchase of traditional and regional products. The price has an important impact on decision in terms of purchase.
Amin, Rucha; Teli, Despoina; James, Patrick; Bourikas, Leonidas
2016-01-01
Adaptive comfort theory states that over time people adapt to their normal environment. Therefore, people from different climates are expected to have different thermal preferences and behaviours, which could lead to ‘performance gap’ in buildings with occupants of diverse climate backgrounds. This study investigates the influence of occupants’ thermal history on use of controls and indoor temperature preference in a newly built halls of residence building complex in Southampton, UK, which pr...
Cofer, Kevin D; Hollis, Robert H; Goss, Lauren; Morris, Melanie S; Porterfield, John R; Chu, Daniel I
2018-02-23
.049). None of the 16 surgical milestone scores were significantly associated with burnout. Burnout is present in surgery residents and associated with emotional intelligence. There was no association of burnout with USMLE scores, ABSITE percentile, or surgical milestones. Traditional methods of assessing resident performance may not be capturing burnout and strategies to reduce burnout should consider targeting emotional intelligence. Published by Elsevier Inc.
Moore, Graham F; Williams, Annie; Moore, Laurence; Murphy, Simon
2013-04-18
This exploratory trial examines the feasibility of implementing a social norms marketing campaign to reduce student drinking in universities in Wales, and evaluating it using cluster randomised trial methodology. Fifty residence halls in 4 universities in Wales were randomly assigned to intervention or control arms. Web and paper surveys were distributed to students within these halls (n = 3800), assessing exposure/contamination, recall of and evaluative responses to intervention messages, perceived drinking norms and personal drinking behaviour. Measures included the Drinking Norms Rating Form, the Daily Drinking Questionnaire and AUDIT-C. A response rate of 15% (n = 554) was achieved, varying substantially between sites. Intervention posters were seen by 80% and 43% of students in intervention and control halls respectively, with most remaining materials seen by a minority in both groups. Intervention messages were rated as credible and relevant by little more than half of students, though fewer felt they would influence their behaviour, with lighter drinkers more likely to perceive messages as credible. No differences in perceived norms were observed between intervention and control groups. Students reporting having seen intervention materials reported lower descriptive and injunctive norms than those who did not. Attention is needed to enhancing exposure, credibility and perceived relevance of intervention messages, particularly among heavier drinkers, before definitive evaluation can be recommended. A definitive evaluation would need to consider how it would achieve sufficient response rates, whilst hall-level cluster randomisation appears subject to a significant degree of contamination. ISRCTN: ISRCTN48556384.
Sustainable livable housing: A review of what traditional urban areas residents find important
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Musibau Lukuman
2017-09-01
Full Text Available Sustainable livable housing is pre-condition for healthy living, improve quality of life and critical to economic and social survival. It also encompasses various aspects that predominantly depend on economic, social, cultural and environmental (ESCE conditions within the locality. To this end, this paper seeks to explore, classify and assess the sustainable livable housing attributes from the existing literatures through content analysis. A review of literature revealed a total of ninety two (92 constructs, which were further grouped nine (9 livable housing-related attributes groups. Well-structured questionnaires were administered to residents of traditional urban areas (TUA of Iwo Osun State, Nigeria with ninety two (92 constructs on Likert scale. Data were analyzed using descriptive statistic and relative importance index (RII. Out of (92 constructs from nine (9 livable housing-related attributes groups, the results identified seventy eight (78 important attributes (i.e. 35 most important and 43 important across groups and construct that TUA residents found important. Over RII was 0.409 for overall assessment of sustainable livable housing condition by TUA residents indicating that TUA residents are dissatisfied with their current housing conditions.
Klerman, Elizabeth B; Beckett, Scott A; Landrigan, Christopher P
2016-09-13
In 2011 the U.S. Accreditation Council for Graduate Medical Education began limiting first year resident physicians (interns) to shifts of ≤16 consecutive hours. Controversy persists regarding the effectiveness of this policy for reducing errors and accidents while promoting education and patient care. Using a mathematical model of the effects of circadian rhythms and length of time awake on objective performance and subjective alertness, we quantitatively compared predictions for traditional intern schedules to those that limit work to ≤ 16 consecutive hours. We simulated two traditional schedules and three novel schedules using the mathematical model. The traditional schedules had extended duration work shifts (≥24 h) with overnight work shifts every second shift (including every third night, Q3) or every third shift (including every fourth night, Q4) night; the novel schedules had two different cross-cover (XC) night team schedules (XC-V1 and XC-V2) and a Rapid Cycle Rotation (RCR) schedule. Predicted objective performance and subjective alertness for each work shift were computed for each individual's schedule within a team and then combined for the team as a whole. Our primary outcome was the amount of time within a work shift during which a team's model-predicted objective performance and subjective alertness were lower than that expected after 16 or 24 h of continuous wake in an otherwise rested individual. The model predicted fewer hours with poor performance and alertness, especially during night-time work hours, for all three novel schedules than for either the traditional Q3 or Q4 schedules. Three proposed schedules that eliminate extended shifts may improve performance and alertness compared with traditional Q3 or Q4 schedules. Predicted times of worse performance and alertness were at night, which is also a time when supervision of trainees is lower. Mathematical modeling provides a quantitative comparison approach with potential to aid
Hou, Yang; Shi, Jiangang; Lin, Yanping; Chen, Huajiang; Yuan, Wen
2018-06-01
The cervical screw placement is one of the most difficult procedures in spine surgery, which often needs a long period of repeated practices and could cause screw placement-related complications. We performed this cadaver study to investigate the effectiveness of virtual surgical training system (VSTS) on cervical pedicle screw instrumentation for residents. A total of ten novice residents were randomly assigned to two groups: the simulation training (ST) group (n = 5) and control group (n = 5). The ST group received a surgical training of cervical pedicle screw placement on VSTS and the control group was given an introductory teaching session before cadaver test. Ten fresh adult spine specimens including 6 males and 4 females were collected, and were randomly allocated to the two groups. The bilateral C3-C6 pedicle screw instrumentation was performed in the specimens of the two groups, respectively. After instrumentation, screw positions of the two groups were evaluated by image examinations. There was significantly statistical difference in screw penetration rates between the ST (10%) and control group (62.5%, P VSTS as an advanced training tool exhibited promising effects on improving performance of novice residents in cervical pedicle screw placement compared with the traditional teaching methods.
Fisher, Nelli; Bernstein, Peter S; Satin, Andrew; Pardanani, Setul; Heo, Hye; Merkatz, Irwin R; Goffman, Dena
2010-10-01
To compare eclampsia and magnesium toxicity management among residents randomly assigned to lecture or simulation-based education. Statified by year, residents (n = 38) were randomly assigned to 3 educational intervention groups: Simulation→Lecture, Simulation, and Lecture. Postintervention simulations were performed for all and scored using standardized lists. Maternal, fetal, eclampsia management, and magnesium toxcity scores were assigned. Mann-Whitney U, Wilcoxon rank sum and χ(2) tests were used for analysis. Postintervention maternal (16 and 15 vs 12; P < .05) and eclampsia (19 vs 16; P < .05) scores were significantly better in simulation based compared with lecture groups. Postintervention magnesium toxcitiy and fetal scores were not different among groups. Lecture added to simulation did not lead to incremental benefit when eclampsia scores were compared between Simulation→Lecture and Simulation (19 vs 19; P = nonsignificant). Simulation training is superior to traditional lecture alone for teaching crucial skills for the optimal management of both eclampsia and magnesium toxicity, 2 life-threatening obstetric emergencies. Published by Mosby, Inc.
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…
Martinez, William; Lehmann, Lisa Soleymani; Thomas, Eric J; Etchegaray, Jason M; Shelburne, Julia T; Hickson, Gerald B; Brady, Donald W; Schleyer, Anneliese M; Best, Jennifer A; May, Natalie B; Bell, Sigall K
2017-11-01
Open communication between healthcare professionals about care concerns, also known as 'speaking up', is essential to patient safety. Compare interns' and residents' experiences, attitudes and factors associated with speaking up about traditional versus professionalism-related safety threats. Anonymous, cross-sectional survey. Six US academic medical centres, 2013-2014. 1800 medical and surgical interns and residents (47% responded). Attitudes about, barriers and facilitators for, and self-reported experience with speaking up. Likelihood of speaking up and the potential for patient harm in two vignettes. Safety Attitude Questionnaire (SAQ) teamwork and safety scales; and Speaking Up Climate for Patient Safety (SUC-Safe) and Speaking Up Climate for Professionalism (SUC-Prof) scales. Respondents more commonly observed unprofessional behaviour (75%, 628/837) than traditional safety threats (49%, 410/837); pbarrier to speaking up about unprofessional behaviour compared with traditional safety threats (58%, 482/837 vs 42%, 348/837; psafety vignette, even when they perceived high potential patient harm (20%, 49/251 vs 71%, 179/251; psafety vignette (OR 1.90, 99% CI 1.36 to 2.66 and 1.46, 1.02 to 2.09, respectively), while only a positive perception of SUC-Prof was associated with speaking up in the professionalism vignette (1.76, 1.23 to 2.50). Interns and residents commonly observed unprofessional behaviour yet were less likely to speak up about it compared with traditional safety threats even when they perceived high potential patient harm. Measuring SUC-Safe, and particularly SUC-Prof, may fill an existing gap in safety culture assessment. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.
Alipour, Sadaf; Moini, Ashraf; Jafari-Adli, Shahrzad; Gharaie, Nooshin; Mansouri, Khorshid
2012-01-01
Mobile learning enables users to interact with educational resources while in variable locations. Medical students in residency positions need to assimilate considerable knowledge besides their practical training and we therefore aimed to evaluate the impact of using short message service via cell phone as a learning tool in residents of Obstetrics and Gynecology in our hospital. We sent short messages including data about breast cancer to the cell phones of 25 residents of gynecology and obstetrics and asked them to study a well-designed booklet containing another set of information about the disease in the same period. The rate of learning derived from the two methods was compared by pre- and post-tests and self-satisfaction assessed by a relevant questionnaire at the end of the program. The mobile learning method had a significantly better effect on learning and created more interest in the subject. Learning via receiving SMS can be an effective and appealing method of knowledge acquisition in higher levels of education.
DEFF Research Database (Denmark)
Otto, Ton
2016-01-01
: beliefs, practices, institutions, and also things. In this sense, the meaning of the term in social research is very close to its usage in common language and is not always theoretically well developed (see Shils, 1971: 123). But the concept of tradition has also been central to major theoretical debates...... on the nature of social change, especially in connection with the notion of modernity. Here tradition is linked to various forms of agency as a factor of both stability and intentional change....
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...
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...
Directory of Open Access Journals (Sweden)
Khuram Pervez Amber
2018-06-01
Full Text Available University buildings, such as student residence halls with year-round consistent energy demands, offer strong opportunities for Combined Heat and Power (CHP systems. The economic and environmental feasibility of a CHP project is strongly linked with its optimum sizing. This study aims to undertake such an assessment for a CHP system for a student residence hall located in London, the United Kingdom (UK. The study also aims to undertake a sensitivity analysis to investigate the effect of different parameters on the project’s economics. Necessary data are collected via interviews with the University’s Energy Manager. Modeling of the CHP system is performed using the London South Bank University (LSBU, London, the UK CHP model. Results demonstrate that optimum sizing of CHP is crucial for achieving higher economic and environmental benefits and strongly depends on the authenticity of the energy consumption data, based on which the CHP is being sized. Use of incorrect energy data could result in an undersized or oversized CHP system, where an oversized system will result in higher negative results compared to an undersized system. Finally, Monto Carlo statistical analysis shows that electricity price is the significant factor that could affect the project’s economics. With an increasing spark gap, the payback period decreases, and vice versa.
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.
Curtis, Henry A; Trang, Karen; Chason, Kevin W; Biddinger, Paul D
2018-02-01
Introduction Great demands have been placed on disaster medicine educators. There is a need to develop innovative methods to educate Emergency Physicians in the ever-expanding body of disaster medicine knowledge. The authors sought to demonstrate that video-based learning (VBL) could be a promising alternative to traditional learning methods for teaching disaster medicine core competencies. Hypothesis/Problem The objective was to compare VBL to traditional lecture (TL) for instructing Emergency Medicine residents in the American College of Emergency Physicians (ACEP; Irving, Texas USA) disaster medicine core competencies of patient triage and decontamination. A randomized, controlled pilot study compared two methods of instruction for mass triage, decontamination, and personal protective equipment (PPE). Emergency Medicine resident learning was measured with a knowledge quiz, a Likert scale measuring comfort, and a practical exercise. An independent samples t-test compared the scoring of the VBL with the TL group. Twenty-six residents were randomized to VBL (n=13) or TL (n=13). Knowledge score improvement following video (14.9%) versus lecture (14.1%) did not differ significantly between the groups (P=.74). Comfort score improvement also did not differ (P=.64) between video (18.3%) and lecture groups (15.8%). In the practical skills assessment, the VBL group outperformed the TL group overall (70.4% vs 55.5%; Plearning vs traditional lecture for instructing emergency medicine residents in disaster medicine principles of mass triage, decontamination, and personal protective equipment. Prehosp Disaster Med. 2018;33(1):7-12.
Colvard, Benjamin; Shames, Murray; Schanzer, Andres; Rectenwald, John; Chaer, Rabih; Lee, Jason T
2015-10-01
The first 2 integrated vascular residents in the United States graduated in 2012, and in 2013, 11 more entered the job market. The purpose of this study was to compare the job search experiences of the first cohort of integrated 0 + 5 graduates to their counterparts completing traditional 5 + 2 fellowship programs. An anonymous, Web-based, 15-question survey was sent to all 11 graduating integrated residents in 2013 and to the 25 corresponding 5 + 2 graduating fellows within the same institution. Questions focused on the following domains: training experience, job search timelines and outcomes, and overall satisfaction with each training paradigm. Survey response was nearly 81% for the 0 + 5 graduates and 64% for the 5 + 2 graduates. Overall, there was no significant difference between residents and fellows in the operative experience obtained as measured by the number of open and endovascular cases logged. Dedicated research time during the entire training period was similar between residents and fellows. Nearly all graduates were extremely satisfied with their training and had positive experiences during their job searches with respect to starting salaries, numbers of offers, and desired practice type. More 0 + 5 residents chose academic and mixed practices over private practices compared with 5 + 2 fellowship graduates. Although longer term data are needed to understand the impact of the addition of 0 + 5 graduating residents to the vascular surgery work force, preliminary survey results suggest that both training paradigms (0 + 5 and 5 + 2) provide positive training experiences that result in excellent job search experiences. Based on the current and future need for vascular surgeons in the work force, the continued growth and expansion of integrated 0 + 5 vascular surgery residency positions as an alternative to traditional fellowship training is thus far justified. Copyright © 2015 Elsevier Inc. All rights reserved.
Experimental halls workshop summary
International Nuclear Information System (INIS)
Thorndike, A.
1976-01-01
A brief discussion is given of: (1) pros and cons of open areas as compared with enclosed halls; (2) experimental hall needs of ep, anti p p, and other options; (3) hall for the lepton detector; and, (4) hall for the hadron spectrometer
Experimental halls workshop summary
International Nuclear Information System (INIS)
Thorndike, A.
1976-01-01
On May 26 and 27, 1976, approximately 50 people met for an informal workshop on plans for experimental halls for ISABELLE. Plans as they exist in the May 1976 version of the ISABELLE proposal were presented. Discussions were held on the following four general topics by separate working groups: (1) pros and cons of open areas as compared with enclosed halls; (2) experimental hall needs of ep, anti pp, and other options; (3) hall for the lepton detector; and (4) hall for the hadron spectrometer. The planning for experimental halls at PEP, the hall for the lepton detector, the hadron spectrometer, and open areas are discussed
Experimental halls workshop summary
International Nuclear Information System (INIS)
Thorndike, A.
1976-01-01
At the experimental halls workshop, discussions were held on: (1) open areas as compared with enclosed halls; (2) the needs of ep, anti pp, and other options; (3) the hall for the lepton detector; and (4) the hall for the hadron spectrometer. The value of different possibilities for the future experimental program was explored. A number of suggestions emerged which will be used as the design of the experimental halls progresses
Oğuz, Hatice Şule
2014-01-01
An attempt to write an article that focuses on Stuart Hall’s work following his death requires addressing such issues such as the New Left,BirminghamSchool, British Cultural Studies, racism, post-colonialism, resistance, hegemony, sub-cultures, reception studies, popular culture, negotiated reading, identity and ethnicity. As Grossberg (2006) notes it is pretty difficult to identify any single position, interest, tradition or methodology in Hall’s work. The “multi-emphasis” in his works incre...
Soares, William E; Sohoni, Aparajita; Hern, Herbert G; Wills, Charlotte P; Alter, Harrison J; Simon, Barry C
2015-01-01
The multiple mini-interview (MMI) is a validated interview technique used primarily to evaluate medical school applicants. No study has compared MMIs with traditional interviews (TIs) in the evaluation of U.S. emergency medicine residency (EMR) applicants. During the 2011-2012 interview season, a four-station MMI was incorporated into the interview process for EMR applicants at Alameda Health System-Highland Hospital (AHS). A postinterview anonymous questionnaire was offered to all applicants after they submitted their rank lists but prior to release of National Residency Matching Program results. Respondents rated their perceptions of the MMI and TI on a five-point Likert scale. McNemar chi-square test was used to explore differences in respondents' perceptions of interview styles. One hundred ten interviewees completed the survey (73%). Overall, applicants found the TI more enjoyable than the MMI process (98 [89%] compared with 48 [44%], McNemar chi-square=28.66, P<.01) and preferred the TI process to the MMI (66 [60%] compared with 9 [10%], McNemar chi-square=40.81, P<.01). Sixteen applicants (14%) indicated that the use of the MMI would negatively affect their ranking of the program. In contrast to prior studies, U.S. EMR applicants to AHS preferred the TI to the MMI. Further investigation into the use of the MMI for selecting U.S. EMR applicants is warranted.
Cryogenic microsize Hall sensors
International Nuclear Information System (INIS)
Kvitkovic, J.; Polak, M.
1993-01-01
Hall sensors have a variety of applications in magnetic field measurements. The active area of the Hall sensor does not play an important role in measuring of homogeneous magnetic field. Actually Hall sensors are widely used to measure profiles of magnetic fields produced by magnetization currents in samples of HTC superconductors, as well as of LTC ones. Similar techniques are used to measure magnetization of both HTC and LTC superconductors. In these cases Hall sensor operates in highly inhomogeneous magnetic fields. Because of that, Hall sensors with very small active area are required. We developed and tested Hall sensors with active area 100 μm x 100 μm - type M and 50 μm x 50 μm - type V. Here we report on the most imporant parameters of these units, as well as on their properties as differential magnetometer. (orig.)
Kim, Bom Soo
2018-05-01
We discuss the contribution of magnetic Skyrmions to the Hall viscosity and propose a simple way to identify it in experiments. The topological Skyrmion charge density has a distinct signature in the electric Hall conductivity that is identified in existing experimental data. In an electrically neutral system, the Skyrmion charge density is directly related to the thermal Hall conductivity. These results are direct consequences of the field theory Ward identities, which relate various physical quantities based on symmetries and have been previously applied to quantum Hall systems.
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.
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...
International Nuclear Information System (INIS)
El-Arabi, N. M.
1993-01-01
Transport phenomena in two dimensional semiconductors have revealed unusual properties. In this thesis these systems are considered and discussed. The theories explain the Integral Quantum Hall Effect (IQHE) and the Fractional Quantum Hall Effect (FQHE). The thesis is composed of five chapters. The first and the second chapters lay down the theory of the IQHE, the third and fourth consider the theory of the FQHE. Chapter five deals with the statistics of particles in two dimension. (author). Refs
Hall viscosity of hierarchical quantum Hall states
Fremling, M.; Hansson, T. H.; Suorsa, J.
2014-03-01
Using methods based on conformal field theory, we construct model wave functions on a torus with arbitrary flat metric for all chiral states in the abelian quantum Hall hierarchy. These functions have no variational parameters, and they transform under the modular group in the same way as the multicomponent generalizations of the Laughlin wave functions. Assuming the absence of Berry phases upon adiabatic variations of the modular parameter τ, we calculate the quantum Hall viscosity and find it to be in agreement with the formula, given by Read, which relates the viscosity to the average orbital spin of the electrons. For the filling factor ν =2/5 Jain state, which is at the second level in the hierarchy, we compare our model wave function with the numerically obtained ground state of the Coulomb interaction Hamiltonian in the lowest Landau level, and find very good agreement in a large region of the complex τ plane. For the same example, we also numerically compute the Hall viscosity and find good agreement with the analytical result for both the model wave function and the numerically obtained Coulomb wave function. We argue that this supports the notion of a generalized plasma analogy that would ensure that wave functions obtained using the conformal field theory methods do not acquire Berry phases upon adiabatic evolution.
International Nuclear Information System (INIS)
Klitzing von, K.
1989-01-01
The quantized Hall effect is theoretically explained in detail as are its basic properties. The explanation is completed with the pertinent mathematical relations and illustrative figures. Experimental data are critically assessed obtained by quantum transport measurement in a magnetic field on two-dimensional systems. The results are reported for a MOSFET silicon transistor and for GaAs-Al x Ga 1-x As heterostructures. The application is discussed of the quantized Hall effect in determining the fine structure constant or in implementing the resistance standard. (M.D.). 27 figs., 57 refs
Intrinsic superspin Hall current
Linder, Jacob; Amundsen, Morten; Risinggârd, Vetle
2017-09-01
We discover an intrinsic superspin Hall current: an injected charge supercurrent in a Josephson junction containing heavy normal metals and a ferromagnet generates a transverse spin supercurrent. There is no accompanying dissipation of energy, in contrast to the conventional spin Hall effect. The physical origin of the effect is an antisymmetric spin density induced among transverse modes ky near the interface of the superconductor arising due to the coexistence of p -wave and conventional s -wave superconducting correlations with a belonging phase mismatch. Our predictions can be tested in hybrid structures including thin heavy metal layers combined with strong ferromagnets and ordinary s -wave superconductors.
International Nuclear Information System (INIS)
Avdonin, A.; Skupiński, P.; Grasza, K.
2016-01-01
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.
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.
Granberg, Donald; Brown, Thad A.
1995-01-01
Examines people's behavior in the Monty Hall Dilemma (MHD), in which a person must make two decisions to win a prize. In a series of five studies, found that people misapprehend probabilities in the MHD. Discusses the MHD's relation to illusion of control, belief perseverance, and the status quo bias. (RJM)
Laurent Guiraud
2000-01-01
General view of the Isotope-Separator On-Line (ISOLDE) hall. ISOLDE is dedicated to the production of a large variety of radioactive ion beams for many different experiments. Rare isotopes can be produced allowing the study of spectra for neutrino beam production.
Czech Academy of Sciences Publication Activity Database
Nagaosa, N.; Sinova, Jairo; Onoda, S.; MacDonald, A. H.; Ong, N. P.
2010-01-01
Roč. 82, č. 2 (2010), s. 1539-1592 ISSN 0034-6861 Institutional research plan: CEZ:AV0Z10100521 Keywords : anomalous Hall effect * spintronics Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 51.695, year: 2010
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. Copyright © 2011 Elsevier Inc. All rights reserved.
High-performance LED luminaire for sports hall
Lee, Xuan-Hao; Yang, Jin-Tsung; Chien, Wei-Ting; Chang, Jung-Hsuan; Lo, Yi-Chien; Lin, Che-Chu; Sun, Ching-Cherng
2015-09-01
In this paper, we present a luminaire design with anti-glare and energy-saving effects for sports hall. Compared with traditional lamps using in a badminton court, the average illuminance on the ground of the proposed LED luminaire is enhanced about 300%. Besides, the uniformity is obviously enhanced and improved. The switch-on speed of lighting in sports hall is greatly reduced from 5-10 minutes to 1 second. The simulation analysis and the corresponding experiment results are demonstrated.
A Small Modular Laboratory Hall Effect Thruster
Lee, Ty Davis
Electric propulsion technologies promise to revolutionize access to space, opening the door for mission concepts unfeasible by traditional propulsion methods alone. The Hall effect thruster is a relatively high thrust, moderate specific impulse electric propulsion device that belongs to the class of electrostatic thrusters. Hall effect thrusters benefit from an extensive flight history, and offer significant performance and cost advantages when compared to other forms of electric propulsion. Ongoing research on these devices includes the investigation of mechanisms that tend to decrease overall thruster efficiency, as well as the development of new techniques to extend operational lifetimes. This thesis is primarily concerned with the design and construction of a Small Modular Laboratory Hall Effect Thruster (SMLHET), and its operation on argon propellant gas. Particular attention was addressed at low-cost, modular design principles, that would facilitate simple replacement and modification of key thruster parts such as the magnetic circuit and discharge channel. This capability is intended to facilitate future studies of device physics such as anomalous electron transport and magnetic shielding of the channel walls, that have an impact on thruster performance and life. Preliminary results demonstrate SMLHET running on argon in a manner characteristic of Hall effect thrusters, additionally a power balance method was utilized to estimate thruster performance. It is expected that future thruster studies utilizing heavier though more expensive gases like xenon or krypton, will observe increased efficiency and stability.
Sinova, Jairo; Valenzuela, Sergio O.; Wunderlich, J.; Back, C. H.; Jungwirth, T.
2015-10-01
Spin Hall effects are a collection of relativistic spin-orbit coupling phenomena in which electrical currents can generate transverse spin currents and vice versa. Despite being observed only a decade ago, these effects are already ubiquitous within spintronics, as standard spin-current generators and detectors. Here the theoretical and experimental results that have established this subfield of spintronics are reviewed. The focus is on the results that have converged to give us the current understanding of the phenomena, which has evolved from a qualitative to a more quantitative measurement of spin currents and their associated spin accumulation. Within the experimental framework, optical-, transport-, and magnetization-dynamics-based measurements are reviewed and linked to both phenomenological and microscopic theories of the effect. Within the theoretical framework, the basic mechanisms in both the extrinsic and intrinsic regimes are reviewed, which are linked to the mechanisms present in their closely related phenomenon in ferromagnets, the anomalous Hall effect. Also reviewed is the connection to the phenomenological treatment based on spin-diffusion equations applicable to certain regimes, as well as the spin-pumping theory of spin generation used in many measurements of the spin Hall angle. A further connection to the spin-current-generating spin Hall effect to the inverse spin galvanic effect is given, in which an electrical current induces a nonequilibrium spin polarization. This effect often accompanies the spin Hall effect since they share common microscopic origins. Both can exhibit the same symmetries when present in structures comprising ferromagnetic and nonmagnetic layers through their induced current-driven spin torques or induced voltages. Although a short chronological overview of the evolution of the spin Hall effect field and the resolution of some early controversies is given, the main body of this review is structured from a pedagogical
Zheng Manqing: The Memorial Hall and Legacy of the Master of Five Excellences in Taiwan
Directory of Open Access Journals (Sweden)
Russ Mason
2012-07-01
Full Text Available Professor Zheng Manqing (1902-1975, a fine artist and a notable taijiquan disciple of Yang Chengfu, emigrated to Taiwan in 1949 following the Chinese civil war between the Guomindang and Maoist factions. Under Republic of China President Chiang Kai-shek’s Cultural Renaissance Movement, Zheng played an important role in preserving the cultural treasures of traditional China. During the period of Mao Zedong’s Cultural Revolution when the Mainland was veiled to foreign eyes behind the Bamboo Curtain, Zheng was instrumental in introducing taijiquan and other elements of Chinese culture to the West. Zheng passed away at his home in Yonghe, Taiwan in 1975 but not before establishing an international reputation for his mastery in taijiquan and other arts. Recently, a portion of his former residence was converted into a memorial hall (the Zheng Manqing Jinian Guan by senior students interested in preserving his martial tradition, paintings, calligraphy, and other artifacts. This article provides a brief history of Zheng’s life and his legacy in Taiwan, as well as a photographic tour of the Zheng Manqing Memorial Hall.
International Nuclear Information System (INIS)
Greiter, M.
1992-01-01
This dissertation contains a collection of individual articles on various topics. Their significance in the corresponding field as well as connections between them are emphasized in a general and comprehensive introduction. In the first article, the author explores the consequences for macroscopic effective Lagrangians of assuming that the momentum density is proportional to the flow of conserved current. The universal corrections obtained for the macroscopic Lagrangian of a superconductor describe the London Hall effect, and provide a fully consistent derivation of it. In the second article, a heuristic principle is proposed for quantized Hall states: the existence and incompressibility of fractionally quantized Hall states is explained by an argument based on an adiabatic localization of magnetic flux, the process of trading uniform flux for an equal amount of fictitious flux attached to the particles. This principle is exactly implemented in the third article. For a certain class of model Hamiltonians, the author obtains Laughlin's Jastrow type wave functions explicitly from a filled Landau level, by smooth extrapolation in quantum statistics. The generalization of this analysis to the torus geometry shows that theorems restricting the possibilities of quantum statistics on closed surfaces are circumvented in the presence of a magnetic field. In the last article, the existence is proposed of a novel incompressible quantum liquid, a paired Hall state, at a half filled Landau level. This state arises adiabatically from free fermions in zero magnetic field, and reduces to a state previously proposed by Halperin in the limit of tightly bound pairs. It supports unusual excitations, including neutral fermions and charge e/4 anyons with statistical parameter θ = π/8
Energy Technology Data Exchange (ETDEWEB)
1984-08-01
This report demonstrates the economic viability of an exterior rewrap retrofit performed on a public community facility for the performing arts. This facility originally consisted of two mess halls built by the American army. The exterior retrofit consisted of constructing a super-insulated passageway to link the two halls as well as completely wrapping the facility with six millimetre polyethylene to provide an airtight barrier. The roofs and walls were reinsulated and insulation levels were increased to RSI 10.5 in the ceilings and RSI 7.7 in the walls. The installation of a propane fuelled furnace was also included in the retrofit package. Prior to the renovations and retrofitting, the Guild Hall facility was almost unusable. The demonstration project transformed the cold, drafty buildings into an attractive, comfortable and functional centre for the performing arts. Heating requirements have been reduced to 500 MJ/m {sup 2} of floor space annually compared to a predicted 1,760 MJ/m{sup 2} of floor space based on HOTCAN analysis of the heating requirements without the energy conservation measures. 9 figs., 10 tabs.
Quantum critical Hall exponents
Lütken, C A
2014-01-01
We investigate a finite size "double scaling" hypothesis using data from an experiment on a quantum Hall system with short range disorder [1-3]. For Hall bars of width w at temperature T the scaling form is w(-mu)T(-kappa), where the critical exponent mu approximate to 0.23 we extract from the data is comparable to the multi-fractal exponent alpha(0) - 2 obtained from the Chalker-Coddington (CC) model [4]. We also use the data to find the approximate location (in the resistivity plane) of seven quantum critical points, all of which closely agree with the predictions derived long ago from the modular symmetry of a toroidal sigma-model with m matter fields [5]. The value nu(8) = 2.60513 ... of the localisation exponent obtained from the m = 8 model is in excellent agreement with the best available numerical value nu(num) = 2.607 +/- 0.004 derived from the CC-model [6]. Existing experimental data appear to favour the m = 9 model, suggesting that the quantum Hall system is not in the same universality class as th...
Topological Hall and Spin Hall Effects in Disordered Skyrmionic Textures
N'diaye, P. B.; Akosa, C. A.; Manchon, A.
2016-01-01
We carry out a throughout 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-B\\"uttiker 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 found that the adiabatic a...
Quantum hall effect. A perspective
International Nuclear Information System (INIS)
Aoki, Hideo
2006-01-01
Novel concepts and phenomena are emerging recently in the physics of quantum Hall effect. This article gives an overview, which starts from the fractional quantum Hall system viewed as an extremely strongly correlated system, and move on to present various phenomena involving internal degrees of freedom (spin and layer), non-equilibrium and optical properties, and finally the spinoff to anomalous Hall effect and the rotating Bose-Einstein condensate. (author)
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.
Czech Academy of Sciences Publication Activity Database
Wunderlich, Joerg; Park, B.G.; Irvine, A.C.; Zarbo, Liviu; Rozkotová, E.; Němec, P.; Novák, Vít; Sinova, Jairo; Jungwirth, Tomáš
2010-01-01
Roč. 330, č. 6012 (2010), s. 1801-1804 ISSN 0036-8075 R&D Projects: GA AV ČR KAN400100652; GA MŠk LC510 EU Projects: European Commission(XE) 215368 - SemiSpinNet Grant - others:AV ČR(CZ) AP0801 Program:Akademická prémie - Praemium Academiae Institutional research plan: CEZ:AV0Z10100521 Keywords : spin Hall effect * spintronics * spin transistor Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 31.364, year: 2010
Quantum Hall Electron Nematics
MacDonald, Allan
In 2D electron systems hosted by crystals with hexagonal symmetry, electron nematic phases with spontaneously broken C3 symmetry are expected to occur in the quantum Hall regime when triplets of Landau levels associated with three different Fermi surface pockets are partially filled. The broken symmetry state is driven by intravalley Coulombic exchange interactions that favor spontaneously polarized valley occupations. I will discuss three different examples of 2D electron systems in which this type of broken symmetry state is expected to occur: i) the SnTe (111) surface, ii) the Bi (111) surface. and iii) unbalanced bilayer graphene. This type of quantum Hall electron nematic state has so far been confirmed only in the Bi (111) case, in which the anisotropic quasiparticle wavefunctions of the broken symmetry state were directly imaged. In the SnTe case the nematic state phase boundary is controlled by a competition between intravalley Coulomb interactions and intervalley scattering processes that increase in relative strength with magnetic field. An in-plane Zeeman field alters the phase diagram by lifting the three-fold Landau level degeneracy, yielding a ground state energy with 2 π/3 periodicity as a function of Zeeman-field orientation angle. I will comment on the possibility of observing similar states in the absence of a magnetic field. Supported by DOE Division of Materials Sciences and Engineering Grant DE-FG03-02ER45958.
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...
The National Academies of Sciences, Engineering and Medicine is seeking community input for a study on the future of materials research (MR). Frontiers of Materials Research: A Decadal Survey will look at defining the frontiers of materials research ranging from traditional materials science and engineering to condensed matter physics. Please join members of the study committee for a town hall to discuss future directions for materials research in the United States in the context of worldwide efforts. In particular, input on the following topics will be of great value: progress, achievements, and principal changes in the R&D landscape over the past decade; identification of key MR areas that have major scientific gaps or offer promising investment opportunities from 2020-2030; and the challenges that MR may face over the next decade and how those challenges might be addressed. This study was requested by the Department of Energy and the National Science Foundation. The National Academies will issue a report in 2018 that will offer guidance to federal agencies that support materials research, science policymakers, and researchers in materials research and other adjoining fields. Learn more about the study at http://nas.edu/materials.
Structural Analysis of the Resident Assistant Cultural Diversity Questionnaire
Johnson, Vanessa D.; Kang, Young-Shin; Thompson, George F.
2011-01-01
This study investigated the five-factor structure of the Resident Assistant Cultural Diversity (RACD) instrument, which assesses resident assistant (RA) confidence in addressing issues of cultural diversity in college and university residence halls. The instrument has five components that explore RA confidence: (1) belief in the need for cultural…
Energy consumption of sport halls
Energy Technology Data Exchange (ETDEWEB)
1983-01-01
The energy consumption of Finland's sports halls (ball games halls, ice hockey halls and swimming halls) represent approximately 1% of that of the country's whole building stock. In the light of the facts revealed by the energy study the potential energy saving rate in sports halls is 15-25%. The total savings would be something like FIM 30-40 million per annum, of which about a half would be achieved without energy-economic investments only by changing utilization habits and by automatic control measures. The energy-economic investments are for the most part connected with ventilation and their repayment period is from one to five years. On the basis of the energy study the following specific consumption are presented as target values: swimming halls: heat (kWh/m*H3/a)100, electricity (kWh/m*H3/a)35, water (l/m*H3/a)1000 icehockey halls (warm): heat (kWh/m*H3/a)25, electricity (kWh/m*H3/a)15, water (l/m*H3/a)200, ball games halls (multi-purpose halls): heat (kWh/m*H3/a)30, electricity (kWh/m*H3/a)25, water (l/m*H3/a)130. In the study the following points proved to be the central areas of energy saving in sports halls: 1. Flexible regulation of the temperature in sports spaces on the basis of the sport in question. 2. The ventilation of swimming halls should be adjusted in such a way that the humidity of the hall air would comply with the limit humidity curve determined by the quality of structures and the temperature of the outdoor air. 3. An ice skating hall is an establishment producing condensing energy from 8 to 9 months a year worth of approx. 100.000-150.000 Finnmarks. The development of the recovery of condensing energy has become more important. 4. The ventilation of ball games halls may account for over 50% of the energy consumption of the whole building. Therefore special attention should be paid to the optimatization of ventilation as a whole.
Scanning vector Hall probe microscopy
International Nuclear Information System (INIS)
Cambel, V.; Gregusova, D.; Fedor, J.; Kudela, R.; Bending, S.J.
2004-01-01
We have developed a scanning vector Hall probe microscope for mapping magnetic field vector over magnetic samples. The microscope is based on a micromachined Hall sensor and the cryostat with scanning system. The vector Hall sensor active area is ∼5x5 μm 2 . It is realized by patterning three Hall probes on the tilted faces of GaAs pyramids. Data from these 'tilted' Hall probes are used to reconstruct the full magnetic field vector. The scanning area of the microscope is 5x5 mm 2 , space resolution 2.5 μm, field resolution ∼1 μT Hz -1/2 at temperatures 10-300 K
Can ensemble condition in a hall be improved and measured?
DEFF Research Database (Denmark)
Gade, Anders Christian
1988-01-01
of the ceiling reflectors; and (c) changing the position of the orchestra on the platform. These variables were then tested in full scale experiments in the hall including subjective evaluation by the orchestra in order to verify their effects under practical conditions. New objective parameters, which showed......In collaboration with the Danish Broadcasting Corporation an extensive series of experiments has been carried out in The Danish Radio Concert Hall with the practical purpose of trying to improve the ensemble conditions on the platform for the resident symphony orchestra. First, a series...... very high correlations with the subjective data, also made it possible to compare the improvements with conditions as recently measured in famous European Halls. Besides providing the needed results, the experiments also shed some light on how musicians change their criteria for judging acoustic...
International Nuclear Information System (INIS)
Shen, M.C.; Ebel, D.
1987-01-01
In this paper some new results concerning magnetohydrodynamic (MHD) equations with the Hall current (HC) term in the Ohm's law are presented. For the cylindrical pinch of a compressible HC fluid, it is found that for large time and long wave length the solution to the governing equations exhibits the behavior of solitons as in the case of an ideal MHD model. In some special cases, the HC model appears to be better posed. An open question is whether a simple toroidal equilibrium of an HC fluid with resistivity and viscosity exists. The answer to this question is affirmative if the prescribed velocity on the boundary has a small norm. Furthermore, the equilibrium is also linearly and nonlinearly stable
Cassidy, David C.
2013-03-01
It's July 1945. Germany is in defeat and the atomic bombs are on their way to Japan. Under the direction of Samuel Goudsmit, the Allies are holding some of the top German nuclear scientists-among them Heisenberg, Hahn, and Gerlach-captive in Farm Hall, an English country manor near Cambridge, England. As secret microphones record their conversations, the scientists are unaware of why they are being held or for how long. Thinking themselves far ahead of the Allies, how will they react to the news of the atomic bombs? How will these famous scientists explain to themselves and to the world their failure to achieve even a chain reaction? How will they come to terms with the horror of the Third Reich, their work for such a regime, and their behavior during that period? This one-act play is based upon the transcripts of their conversations as well as the author's historical work on the subject.
International Nuclear Information System (INIS)
Joynt, R.J.
1982-01-01
A general investigation of the electronic structure of two dimensional systems is undertaken with a view towards understanding the quantum Hall effect. The work is limited to the case of a strong perpendicular magnetic field, with a disordered potential and an externally applied electric field. The electrons are treated as noninteracting. First, the scattering theory of the system is worked out. The surprising result is found that a wavepacket will reform after scattering from an isolated potential. Also it will tend to be accelerated in the neighborhood of the scatterer if the potential has bound states. Fredholm theory can then be used to show that the extended states carry an additional current which compensates for the zero current of the bound states. Together, these give the quantized conductance. The complementary case of a smooth random potential is treated by a path-integral approach which exploits the analogies to the classical equations of motion. The Green's function can be calculated approximately, which gives the general character of both the bound and extended states. Also the ratio of these two types of states can be computed for a given potential. The charge density is uniform in first approximation, and the Hall conductance is quantized. Higher-order corrections for more rapidly fluctuating potential are calculated. The most general conditions under which the conductance is quantized are discussed. Because of the peculiar scattering properties of the system, numerical solution of the Schroedinger equation is of interest, both to confirm the analytical results, and for pedagogical reasons. The stability and convergence problems inherent in the computer solution of the problem are analyzed. Results for some model scattering potentials are presented
Hall Effect Gyrators and Circulators
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.
Hamaoka Atomic Energy Hall, Chubu Electric Power Co. , Inc
Energy Technology Data Exchange (ETDEWEB)
Kawasaki, Y [Chubu Electric Power Co. Inc., Nagoya (Japan)
1979-10-01
Hamaoka Nuclear Power Station was constructed in the very large site of about 1.6 million m/sup 2/ surrounded by sand dunes and pine forests at the southern tip of Shizuoka Prefecture. Hamaoka Atomic Energy Hall was built on the right side of this power station. This hall had been planned as a part of the works commemorating the 20th anniversary of the founding of the company, and was opened in August, 1972. The building is of steel frame type, and has two floors of 1135 m/sup 2/ total area. The first floor comprises cinema room, power generation corner and open gallery, and the second floor comprises meeting room, native land corner and observation room. Moreover, there is observation platform on the roof. The purpose of the hall is coexistence and coprosperity with the regional residents, and 13 persons make explanations to visitors having reached to 1.9 million as of the end of June, 1979. It is incorporated in the sightseeing route centering around the Omaezaki lighthouse. The cinema hall accommodates 120 men, and the films concerning nuclear power generation and the construction of a nuclear power plant are shown. In the power generation corner, the explanation on nuclear power generation is made with models and panels. The third hall is being built now as energy corner, and it will be completed in autumn, 1979.
Hamaoka Atomic Energy Hall, Chubu Electric Power Co., Inc
International Nuclear Information System (INIS)
Kawasaki, Yukio
1979-01-01
Hamaoka Nuclear Power Station was constructed in the very large site of about 1.6 million m 2 surrounded by sand dunes and pine forests at the southern tip of Shizuoka Prefecture. Hamaoka Atomic Energy Hall was built on the right side of this power station. This hall had been planned as a part of the works commemorating the 20th anniversary of the founding of the company, and was opened in August, 1972. The building is of steel frame type, and has two floors of 1135 m 2 total area. The first floor comprises cinema room, power generation corner and open gallery, and the second floor comprises meeting room, native land corner and observation room. Moreover, there is observation platform on the roof. The purpose of the hall is coexistence and coprosperity with the regional residents, and 13 persons make explanations to visitors having reached to 1.9 million as of the end of June, 1979. It is incorporated in the sightseeing route centering around the Omaezaki lighthouse. The cinema hall accommodates 120 men, and the films concerning nuclear power generation and the construction of a nuclear power plant are shown. In the power generation corner, the explanation on nuclear power generation is made with models and panels. The third hall is being built now as energy corner, and it will be completed in autumn, 1979. (Kako, I.)
Directory of Open Access Journals (Sweden)
S. E. Evstifeeva
2015-09-01
Full Text Available Aim. To study the association of high-sensitivity C-reactive protein (hsCRP level with socio-demographic, behavioral and traditional risk factors in different regions of the Russian Federation (RF.Material and methods. Data of the multicenter epidemiological study of cardiovascular disease in different regions of the Russian Federation (ESSE-RF were used. Representative sample of the unorganized male and female population aged 25-64 from 6 regions of the Russian Federation was drown. 3407 men and 6354 women (n=9761 were included into the study. Standard questionnaire was applied in all subjects. Gender, age, level of education, place of residence and region of residence, traditional risk factors and diseases were analyzed. HsCRP level (level ≥3.0 mg/l was defined as elevated one was evaluated to detect of indolent inflammation.Results. HsCRP levels in women was significantly higher compared to males (p<0.005. The average prevalence of elevated hsCRP in the regions was 24.2%, for men - 21.4%, and for women - 25.7% (p<0.005. Significant age-related dynamics of hsCRP (p<0.0001 was found. The average level of hsCRP was significantly lower (p<0.0001 in a cohort of persons with higher education against these with lower level of education. Level of hsCRP as well as prevalence of elevated hsCRP level were higher in villagers than this in the urban population (p<0.05. Prevalence of elevated hsCRP in patients with traditional risk factors after adjustment for sex, age, and region of residence showed that the elevated hsCRP was mostly associated with metabolic factors and diseases that were characterized by systemic inflammation.Conclusion. Elevated level of hsCRP (≥3.0 mg/l was significantly associated with female gender, with an older, less educated, and smoking population of Russians. After the multivariate adjustment there remained significant associations (p<0.0001 of elevated hsCRP level with obesity, including abdominal obesity, hyperglycemia
Directory of Open Access Journals (Sweden)
S. E. Evstifeeva
2014-01-01
Full Text Available Aim. To study the association of high-sensitivity C-reactive protein (hsCRP level with socio-demographic, behavioral and traditional risk factors in different regions of the Russian Federation (RF.Material and methods. Data of the multicenter epidemiological study of cardiovascular disease in different regions of the Russian Federation (ESSE-RF were used. Representative sample of the unorganized male and female population aged 25-64 from 6 regions of the Russian Federation was drown. 3407 men and 6354 women (n=9761 were included into the study. Standard questionnaire was applied in all subjects. Gender, age, level of education, place of residence and region of residence, traditional risk factors and diseases were analyzed. HsCRP level (level ≥3.0 mg/l was defined as elevated one was evaluated to detect of indolent inflammation.Results. HsCRP levels in women was significantly higher compared to males (p<0.005. The average prevalence of elevated hsCRP in the regions was 24.2%, for men - 21.4%, and for women - 25.7% (p<0.005. Significant age-related dynamics of hsCRP (p<0.0001 was found. The average level of hsCRP was significantly lower (p<0.0001 in a cohort of persons with higher education against these with lower level of education. Level of hsCRP as well as prevalence of elevated hsCRP level were higher in villagers than this in the urban population (p<0.05. Prevalence of elevated hsCRP in patients with traditional risk factors after adjustment for sex, age, and region of residence showed that the elevated hsCRP was mostly associated with metabolic factors and diseases that were characterized by systemic inflammation.Conclusion. Elevated level of hsCRP (≥3.0 mg/l was significantly associated with female gender, with an older, less educated, and smoking population of Russians. After the multivariate adjustment there remained significant associations (p<0.0001 of elevated hsCRP level with obesity, including abdominal obesity, hyperglycemia
Topological Hall and spin Hall effects in disordered skyrmionic textures
Ndiaye, Papa Birame; Akosa, Collins Ashu; Manchon, Aurelien
2017-01-01
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.
Topological Hall and spin Hall effects in disordered skyrmionic textures
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.
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.
Experimental Studies of Anode Sheath Phenomena in a Hall Thruster Discharge
International Nuclear Information System (INIS)
Dorf, L.; Raitses, Y.; Fisch, N.J.
2004-01-01
Both electron-repelling and electron-attracting anode sheaths in a Hall thruster were characterized by measuring the plasma potential with biased and emissive probes [L. Dorf, Y. Raitses, V. Semenov, and N.J. Fisch, Appl. Phys. Let. 84 (2004) 1070]. In the present work, two-dimensional structures of the plasma potential, electron temperature, and plasma density in the near-anode region of a Hall thruster with clean and dielectrically coated anodes are identified. Possible mechanisms of anode sheath formation in a Hall thruster are analyzed. The path for current closure to the anode appears to be the determining factor in the anode sheath formation process. The main conclusion of this work is that the anode sheath formation in Hall thrusters differs essentially from that in the other gas discharge devices, like a glow discharge or a hollow anode, because the Hall thruster utilizes long electron residence times to ionize rather than high neutral pressures
Nagaosa, Naoto; Sinova, Jairo; Onoda, Shigeki; MacDonald, A. H.; Ong, N. P.
2010-04-01
The anomalous Hall effect (AHE) occurs in solids with broken time-reversal symmetry, typically in a ferromagnetic phase, as a consequence of spin-orbit coupling. Experimental and theoretical studies of the AHE are reviewed, focusing on recent developments that have provided a more complete framework for understanding this subtle phenomenon and have, in many instances, replaced controversy by clarity. Synergy between experimental and theoretical works, both playing a crucial role, has been at the heart of these advances. On the theoretical front, the adoption of the Berry-phase concepts has established a link between the AHE and the topological nature of the Hall currents. On the experimental front, new experimental studies of the AHE in transition metals, transition-metal oxides, spinels, pyrochlores, and metallic dilute magnetic semiconductors have established systematic trends. These two developments, in concert with first-principles electronic structure calculations, strongly favor the dominance of an intrinsic Berry-phase-related AHE mechanism in metallic ferromagnets with moderate conductivity. The intrinsic AHE can be expressed in terms of the Berry-phase curvatures and it is therefore an intrinsic quantum-mechanical property of a perfect crystal. An extrinsic mechanism, skew scattering from disorder, tends to dominate the AHE in highly conductive ferromagnets. The full modern semiclassical treatment of the AHE is reviewed which incorporates an anomalous contribution to wave-packet group velocity due to momentum-space Berry curvatures and correctly combines the roles of intrinsic and extrinsic (skew-scattering and side-jump) scattering-related mechanisms. In addition, more rigorous quantum-mechanical treatments based on the Kubo and Keldysh formalisms are reviewed, taking into account multiband effects, and demonstrate the equivalence of all three linear response theories in the metallic regime. Building on results from recent experiment and theory, a
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....
Gauge invariance and fractional quantized Hall effect
International Nuclear Information System (INIS)
Tao, R.; Wu, Y.S.
1984-01-01
It is shown that gauge invariance arguments imply the possibility of fractional quantized Hall effect; the Hall conductance is accurately quantized to a rational value. The ground state of a system showing the fractional quantized Hall effect must be degenerate; the non-degenerate ground state can only produce the integral quantized Hall effect. 12 references
Investigations of Probe Induced Perturbations in a Hall Thruster
International Nuclear Information System (INIS)
D. Staack; Y. Raitses; N.J. Fisch
2002-01-01
An electrostatic probe used to measure spatial plasma parameters in a Hall thruster generates perturbations of the plasma. These perturbations are examined by varying the probe material, penetration distance, residence time, and the nominal thruster conditions. The study leads us to recommendations for probe design and thruster operating conditions to reduce discharge perturbations, including metal shielding of the probe insulator and operation of the thruster at lower densities
"Hall mees" Linnateatris / Triin Sinissaar
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
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.
Anode sheath in Hall thrusters
International Nuclear Information System (INIS)
Dorf, L.; Semenov, V.; Raitses, Y.
2003-01-01
A set of hydrodynamic equations is used to describe quasineutral plasma in ionization and acceleration regions of a Hall thruster. The electron distribution function and Poisson equation are invoked for description of a near-anode region. Numerical solutions suggest that steady-state operation of a Hall thruster can be achieved at different anode sheath regimes. It is shown that the anode sheath depends on the thruster operating conditions, namely the discharge voltage and the mass flow rate
Chudnovsky, Eugene M.
2007-01-01
An extension of Drude model is proposed that accounts for spin and spin-orbit interaction of charge carriers. Spin currents appear due to combined action of the external electric field, crystal field and scattering of charge carriers. The expression for spin Hall conductivity is derived for metals and semiconductors that is independent of the scattering mechanism. In cubic metals, spin Hall conductivity $\\sigma_s$ and charge conductivity $\\sigma_c$ are related through $\\sigma_s = [2 \\pi \\hbar...
Optimization of Cylindrical Hall Thrusters
International Nuclear Information System (INIS)
Raitses, Yevgeny; Smirnov, Artem; Granstedt, Erik; Fisch, Nathaniel J.
2007-01-01
The cylindrical Hall thruster features high ionization efficiency, quiet operation, and ion acceleration in a large volume-to-surface ratio channel with performance comparable with the state-of-the-art annular Hall thrusters. These characteristics were demonstrated in low and medium power ranges. Optimization of miniaturized cylindrical thrusters led to performance improvements in the 50-200W input power range, including plume narrowing, increased thruster efficiency, reliable discharge initiation, and stable operation.
Optimization of Cylindrical Hall Thrusters
International Nuclear Information System (INIS)
Raitses, Yevgeny; Smirnov, Artem; Granstedt, Erik; Fi, Nathaniel J.
2007-01-01
The cylindrical Hall thruster features high ionization efficiency, quiet operation, and ion acceleration in a large volume-to-surface ratio channel with performance comparable with the state-of-the-art annular Hall thrusters. These characteristics were demonstrated in low and medium power ranges. Optimization of miniaturized cylindrical thrusters led to performance improvements in the 50-200W input power range, including plume narrowing, increased thruster efficiency, reliable discharge initiation, and stable operation
Not your grandfather's concert hall
Cooper, Russell; Malenka, Richard; Griffith, Charles; Friedlander, Steven
2004-05-01
The opening of Judy and Arthur Zankel Hall on 12 September 2003, restores Andrew Carnegie's original 1891 concept of having three outstanding auditoriums of different sizes under one roof, and creates a 21st-century venue for music performance and education. With concerts ranging from early music to avant-garde multimedia productions, from jazz to world music, and from solo recitals to chamber music, Zankel Hall expands the breadth and depth of Carnegie Hall's offerings. It allows for the integration of programming across three halls with minifestivals tailored both to the size and strengths of each hall and to the artists and music to be performed. The new flexible space also provides Carnegie Hall with an education center equipped with advanced communications technology. This paper discusses the unique program planned for this facility and how the architects, theatre consultants, and acousticians developed a design that fulfilled the client's expectations and coordinated the construction of the facility under the floor of the main Isaac Stern Auditorium without having to cancel a single performance.
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).
Faculty Mentoring in Residence Halls: An Experiential Learning Process
Jhaveri, Hemlata
2012-01-01
As more demands are being placed on faculty inside of the classroom, the debate surrounding the feasibility of faculty having the time and resources to be involved outside the classroom continues. At the same time there is a growing concern that in light of current advancements in technology; oral communication skills, basic to human existence is…
International Nuclear Information System (INIS)
Entin-Wohlman, O.
2005-01-01
Full Text:The spin-Hall effect is described. The Rashba and Dresselhaus spin-orbit interactions are both shown to yield the low temperature spin-Hall effect for strongly localized electrons coupled to phonons. A frequency-dependent electric field E(ω) generates a spin-polarization current, normal to E, due to interference of hopping paths. At zero temperature the corresponding spin-Hall conductivity is real and is proportional to ω 2 . At non-zero temperatures the coupling to the phonons yields an imaginary term proportional to ω. The interference also yields persistent spin currents at thermal equilibrium, at E = 0. The contributions from the Dresselhaus and Rashba interactions to the interference oppose each other
[Common household traditional Chinese medicines].
Zhang, Shu-Yuan; Li, Mei; Fu, Dan; Liu, Yang; Wang, Hui; Tan, Wei
2016-02-01
With the enhancement in the awareness of self-diagnosis among residents, it's very common for each family to prepare common medicines for unexpected needs. Meanwhile, with the popularization of the traditional Chinese medicine knowledge, the proportion of common traditional Chinese medicines prepared at residents' families is increasingly higher than western medicines year by year. To make it clear, both pre-research and closed questionnaire research were adopted for residents in Chaoyang District, Beijing, excluding residents with a medical background. Based on the results of data, a analysis was made to define the role and influence on the quality of life of residents and give suggestions for relevant departments to improve the traditional Chinese medicine popularization and promote the traditional Chinese medicine market. Copyright© by the Chinese Pharmaceutical Association.
Men's Identity Development: Issues and Implications for Residence Life
Scott, David A.; Livingston, Wade G.; Havice, Pamela A.; Cawthon, Tony W.
2012-01-01
Young men struggle with privilege and oppression in college and university residence halls just as they do in other educational and social contexts. While discussions and research about adolescent and adult identity development continue, little attention has focused on how a male student's identity development can impact residence life cultures on…
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.
Universal intrinsic spin Hall effect
Czech Academy of Sciences Publication Activity Database
Sinova, J.; Culcer, D.; Sinitsyn, N. A.; Niu, Q.; Jungwirth, Tomáš; MacDonald, A. H.
2004-01-01
Roč. 92, č. 12 (2004), 126603/1-126603/4 ISSN 0031-9007 R&D Projects: GA ČR GA202/02/0912 Institutional research plan: CEZ:AV0Z1010914 Keywords : semiconductor quantum wells * spin-orbit interaction * spin Hall effect Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 7.218, year: 2004
International Nuclear Information System (INIS)
Dhar, S.; Basu, B.; Ghosh, Subir
2007-01-01
We explain the intrinsic spin Hall effect from generic anyon dynamics in the presence of external electromagnetic field. The free anyon is represented as a spinning particle with an underlying non-commutative configuration space. The Berry curvature plays a major role in the analysis
The Other Hall Effect: College Board Physics
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…
Psychiatry residents in a milieu participatory democracy: a resident's view.
Gersten, D
1978-11-01
Psychiatry residents respond with a variety of coping mechanisms to the lack of traditional structure in a milieu participatory democracy. To incorporate themselves into the system they must accept such democratic ideals as equality among staff and patients, group decision making, and free self-expression and give up some of their traditional ideas about staff and patient roles, treatment modalities, and the therapeutic environment. The author was a first-year resident in psychiatry on a university hospital inpatient therapeutic community; he discusses the conflicts between residents, who often adopt a "we-they" attitude, and the permanent staff, whose protectiveness of the ward community reflects their personal commitment to its ideals.
Hall effect in noncommutative coordinates
International Nuclear Information System (INIS)
Dayi, Oemer F.; Jellal, Ahmed
2002-01-01
We consider electrons in uniform external magnetic and electric fields which move on a plane whose coordinates are noncommuting. Spectrum and eigenfunctions of the related Hamiltonian are obtained. We derive the electric current whose expectation value gives the Hall effect in terms of an effective magnetic field. We present a receipt to find the action which can be utilized in path integrals for noncommuting coordinates. In terms of this action we calculate the related Aharonov-Bohm phase and show that it also yields the same effective magnetic field. When magnetic field is strong enough this phase becomes independent of magnetic field. Measurement of it may give some hints on spatial noncommutativity. The noncommutativity parameter θ can be tuned such that electrons moving in noncommutative coordinates are interpreted as either leading to the fractional quantum Hall effect or composite fermions in the usual coordinates
General vibration monitoring: Experimental hall
International Nuclear Information System (INIS)
Jendrzejczyk, J.A.; Wambsganss, M.W.; Smith, R.K.
1993-01-01
The reported vibration data were generated from measurements made on the experimental hall floor on December 2, 1992. At the time of the measurements, the ESRF hydrolevel was set-up in the Early Assembly Area (EAA) of the experimental hall and was being used to measure static displacement (settlement) of the floor. The vibration measurement area was on and adjacent to the EAA, in the vicinity of the ESRF hydrolevel test which was in progress. This report summarizes the objectives, instrumentation, measurement locations, observations, and conclusions, and provides selected results in the form of RMS vs. time plots, and power spectral densities from which frequency information can be derived. Measured response amplitudes were within the vibration criteria established for the APS
Scanning vector Hall probe microscope
Czech Academy of Sciences Publication Activity Database
Fedor, J.; Cambel, V.; Gregušová, D.; Hanzelka, Pavel; Dérer, J.; Volko, J.
2003-01-01
Roč. 74, č. 12 (2003), s. 5105 - 5110 ISSN 0034-6748 Institutional research plan: CEZ:AV0Z2065902 Keywords : VHPM * Hall sensor * Helium cryostat Subject RIV: JB - Sensors, Measurment, Regulation Impact factor: 1.343, year: 2003 http://web. ebscohost .com/ehost/pdf?vid=8&hid=115&sid=a7c0555a-21f4-4932-b1c6-a308ac4dd50b%40sessionmgr2
Samson, Thomas
Nous proposons une methode permettant d'obtenir une expression pour la conductivite de Hall de structures electroniques bidimensionnelles et nous examinons celle -ci a la limite d'une temperature nulle dans le but de verifier l'effet Hall quantique. Nous allons nous interesser essentiellement a l'effet Hall quantique entier et aux effets fractionnaires inferieurs a un. Le systeme considere est forme d'un gaz d'electrons en interaction faible avec les impuretes de l'echantillon. Le modele du gaz d'electrons consiste en un gaz bidimensionnel d'electrons sans spin expose perpendiculairement a un champ magnetique uniforme. Ce dernier est decrit par le potentiel vecteur vec{rm A} defini dans la jauge de Dingle ou jauge symetrique. Conformement au formalisme de la seconde quantification, l'hamiltonien de ce gaz est represente dans la base des etats a un-corps de Dingle |n,m> et exprime ainsi en terme des operateurs de creation et d'annihilation correspondants a_sp{ rm n m}{dag} et a _{rm n m}. Nous supposons de plus que les electrons du niveau fondamental de Dingle interagissent entre eux via le potentiel coulombien. La methode utilisee fait appel a une equation mai tresse a N-corps, de nature quantique et statistique, et verifiant le second principe de la thermodynamique. A partir de celle-ci, nous obtenons un systeme d'equations differentielles appele hierarchie d'equations quantique dont la resolution nous permet de determiner une equation a un-corps, dite de Boltzmann quantique, et dictant l'evolution de la moyenne statistique de l'operateur non-diagonal a _sp{rm n m}{dag } a_{rm n}, _{rm m}, sous l'action du champ electrique applique vec{rm E}(t). C'est sa solution Tr(p(t) a _sp{rm n m}{dag} a_{rm n},_ {rm m}), qui definit la relation de convolution entre la densite courant de Hall vec{rm J}_{rm H }(t) et le champ electrique vec {rm E}(t) dont la transformee de Laplace-Fourier du noyau nous fournit l'expression de la conductivite de Hall desiree. Pour une valeur de
Nematic and Valley Ordering in Anisotropic Quantum Hall Systems
Parameswaran, S. A.; Abanin, D. A.; Kivelson, S. A.; Sondhi, S. L.
2010-03-01
We consider a multi-valley two dimensional electron system in the quantum Hall effect (QHE) regime. We focus on QHE states that arise due to spontaneous breaking of the valley symmetry by the Coulomb interactions. We show that the anisotropy of the Fermi surface in each valley, which is generally present in such systems, favors states where all the electrons reside in one of the valleys. In a clean system, the valley ordering occurs via a finite temperature Ising-like phase transition, which, owing to the Fermi surface anisotropy, is accompanied by the onset of nematic order. In a disordered system, domains of opposite polarization are formed, and therefore long-range valley order is destroyed, however, the resulting state is still compressible. We discuss the transport properties in ordered and disordered regimes, and point out the possible relation of our results to recent experiments in AlAs [1]. [1] Y. P. Shkolnikov, S. Misra, N. C. Bishop, E. P. De Poortere, and M. Shayegan, Observation of Quantum Hall ``Valley Skyrmions", Phys. Rev. Lett. 95, 068809 (2005)[2] D.A. Abanin, S.A. Parameswaran, S.A. Kivelson and S.L. Sondhi, Nematic and Valley Ordering in Anisotropic Quantum Hall Systems, to be published.
Spin Hall effect by surface roughness
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.
Tunneling Anomalous and Spin Hall Effects.
Matos-Abiague, A; Fabian, J
2015-07-31
We predict, theoretically, the existence of the anomalous Hall effect when a tunneling current flows through a tunnel junction in which only one of the electrodes is magnetic. The interfacial spin-orbit coupling present in the barrier region induces a spin-dependent momentum filtering in the directions perpendicular to the tunneling current, resulting in a skew tunneling even in the absence of impurities. This produces an anomalous Hall conductance and spin Hall currents in the nonmagnetic electrode when a bias voltage is applied across the tunneling heterojunction. If the barrier is composed of a noncentrosymmetric material, the anomalous Hall conductance and spin Hall currents become anisotropic with respect to both the magnetization and crystallographic directions, allowing us to separate this interfacial phenomenon from the bulk anomalous and spin Hall contributions. The proposed effect should be useful for proving and quantifying the interfacial spin-orbit fields in metallic and metal-semiconductor systems.
Anomalous Hall effect in polycrystalline Ni films
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.
Temperature Gradient in Hall Thrusters
International Nuclear Information System (INIS)
Staack, D.; Raitses, Y.; Fisch, N.J.
2003-01-01
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
Directory of Open Access Journals (Sweden)
John F. Fisher
2016-05-01
Full Text Available The training of physicians in the past century was based primarily on responsibility and the chain-of-command. Those with the bulk of that responsibility in the fields of pediatrics and internal medicine were residents. Residents trained the medical students and supervised them carefully in caring for patients. Most attending physicians supervised their teams at arm's length, primarily serving as teachers of the finer points of diagnosis and treatment during set periods of the day or week with a perfunctory signature on write-ups or progress notes. Residents endeavored to protect the attending physician from being heavily involved unless they were unsure about a clinical problem. Before contacting the attending physician, a more senior resident would be called. Responsibility was the ultimate teacher. The introduction of diagnosis-related groups by the federal government dramatically changed the health care delivery system, placing greater emphasis on attending physician visibility in the medical record, ultimately resulting in more attending physician involvement in day-to-day care of patients in academic institutions. Without specified content in attending notes, hospital revenues would decline. Although always in charge technically, attending physicians increasingly have assumed the role once dominated by the resident. Using biographical experiences of more than 40 years, the author acknowledges and praises the educational role of responsibility in his own training and laments its declining role in today's students and house staff.
2010-02-19
... Rita C. Hall; Notice of Application Accepted for Filing With the Commision, Soliciting Motions To.... Project No.: 13652-000. c. Date filed: January 11, 2010. d. Applicant: Gary E. Hall and Rita C. Hall. e... Policies Act of 1978, 16 U.S.C. 2705, 2708. h. Applicant Contact: Mr. Gary E. Hall and Ms. Rita C. Hall, P...
Nondestructive hall coefficient measurements using ACPD techniques
Velicheti, Dheeraj; Nagy, Peter B.; Hassan, Waled
2018-04-01
Hall coefficient measurements offer great opportunities as well as major challenges for nondestructive materials characterization. The Hall effect is produced by the magnetic Lorentz force acting on moving charge carriers in the presence of an applied magnetic field. The magnetic perturbation gives rise to a Hall current that is normal to the conduction current but does not directly perturb the electric potential distribution. Therefore, Hall coefficient measurements usually exploit the so-called transverse galvanomagnetic potential drop effect that arises when the Hall current is intercepted by the boundaries of the specimen and thereby produce a measurable potential drop. In contrast, no Hall potential is produced in a large plate in the presence of a uniform normal field at quasi-static low frequencies. In other words, conventional Hall coefficient measurements are inherently destructive since they require cutting the material under tests. This study investigated the feasibility of using alternating current potential drop (ACPD) techniques for nondestructive Hall coefficient measurements in plates. Specifically, the directional four-point square-electrode configuration is investigated with superimposed external magnetic field. Two methods are suggested to make Hall coefficient measurements in large plates without destructive machining. At low frequencies, constraining the bias magnetic field can replace constraining the dimensions of the specimen, which is inherently destructive. For example, when a cylindrical permanent magnet is used to provide the bias magnetic field, the peak Hall voltage is produced when the diameter of the magnet is equal to the diagonal of the square ACPD probe. Although this method is less effective than cutting the specimen to a finite size, the loss of sensitivity is less than one order of magnitude even at very low frequencies. In contrast, at sufficiently high inspection frequencies the magnetic field of the Hall current induces a
Hall magnetohydrodynamics of neutral layers
International Nuclear Information System (INIS)
Huba, J.D.; Rudakov, L.I.
2003-01-01
New analytical and numerical results of the dynamics of inhomogeneous, reversed field current layers in the Hall limit (i.e., characteristic length scales < or approx. the ion inertial length) are presented. Specifically, the two- and three-dimensional evolution of a current layer that supports a reversed field plasma configuration and has a density gradient along the current direction is studied. The two-dimensional study demonstrates that a density inhomogeneity along the current direction can dramatically redistribute the magnetic field and plasma via magnetic shock-like or rarefaction waves. The relative direction between the density gradient and current flow plays a critical role in the evolution of the current sheet. One important result is that the current sheet can become very thin rapidly when the density gradient is directed opposite to the current. The three-dimensional study uses the same plasma and field configuration as the two-dimensional study but is also initialized with a magnetic field perturbation localized along the current channel upstream of the plasma inhomogeneity. The perturbation induces a magnetic wave structure that propagates in the direction of the electron drift (i.e., opposite to the current). The propagating wave structure is a Hall phenomenon associated with magnetic field curvature. The interaction between the propagating wave structure and the evolving current layer can lead to rapid magnetic field line reconnection. The results are applied to laboratory and space plasma processes
Giant anisotropic magnetoresistance in a quantum anomalous Hall insulator
Kandala, Abhinav; Richardella, Anthony; Kempinger, Susan; Liu, Chao-Xing; Samarth, Nitin
2015-01-01
When a three-dimensional ferromagnetic topological insulator thin film is magnetized out-of-plane, conduction ideally occurs through dissipationless, one-dimensional (1D) chiral states that are characterized by a quantized, zero-field Hall conductance. The recent realization of this phenomenon, the quantum anomalous Hall effect, provides a conceptually new platform for studies of 1D transport, distinct from the traditionally studied quantum Hall effects that arise from Landau level formation. An important question arises in this context: how do these 1D edge states evolve as the magnetization is changed from out-of-plane to in-plane? We examine this question by studying the field-tilt-driven crossover from predominantly edge-state transport to diffusive transport in Crx(Bi,Sb)2−xTe3 thin films. This crossover manifests itself in a giant, electrically tunable anisotropic magnetoresistance that we explain by employing a Landauer–Büttiker formalism. Our methodology provides a powerful means of quantifying dissipative effects in temperature and chemical potential regimes far from perfect quantization. PMID:26151318
Quantum Hall effect in quantum electrodynamics
International Nuclear Information System (INIS)
Penin, Alexander A.
2009-01-01
We consider the quantum Hall effect in quantum electrodynamics and find a deviation from the quantum-mechanical prediction for the Hall conductivity due to radiative antiscreening of electric charge in an external magnetic field. A weak dependence of the universal von Klitzing constant on the magnetic field strength, which can possibly be observed in a dedicated experiment, is predicted
Hall devices improve electric motor efficiency
Haeussermann, W.
1979-01-01
Efficiency of electric motors and generators is reduced by radial magnetic forces created by symmetric fields within device. Forces are sensed and counteracted by Hall devices on excitation or control windings. Hall generators directly measure and provide compensating control of anu asymmetry, eliminating additional measurements needed for calibration feedback control loop.
Higher fractions theory of fractional hall effect
International Nuclear Information System (INIS)
Kostadinov, I.Z.; Popov, V.N.
1985-07-01
A theory of fractional quantum Hall effect is generalized to higher fractions. N-particle model interaction is used and the gap is expressed through n-particles wave function. The excitation spectrum in general and the mean field critical behaviour are determined. The Hall conductivity is calculated from first principles. (author)
The role of the men's hall in the development of the Anglo-Saxon superego.
Earl, J W
1983-05-01
This paper is a historical study of ritual space--a bit of psychoanalytic anthropology applied to a particular case, the evolution of the men's hall among the early Anglo-Saxons. I focus particularly on the ritual functions of poetry in the hall, the same poetry which is our major evidence regarding the hall, especially the epic Beowulf. I define the hall as a cultural institution, and redefine the native poetic tradition in relation to the hall's varied ritual life, with which the poetry is so occupied. Though my argument is focused on the hall, it includes a framework of theoretical concerns. Early Anglo-Saxon culture is of anthropological interest chiefly because of its rapid and dramatic emergence from Germanic tribal prehistory into a leading role in the civilization of Christian Europe. The conquest of Britain by the Anglo-Saxons in the fifth and sixth centuries, and their conversion soon afterward, is a case history of the transformations of a tribal society suddenly introduced to the special forces of civilization and the higher religions that control them. The Anglo-Saxons are fascinating in this regard because of the fortuitous developments that prepared for this transformation and made it so successful.
Report of experimental hall subworking group
International Nuclear Information System (INIS)
Miyake, K.; Ohama, T.; Takahashi, K.
1982-01-01
The general plan of constructing the TRISTAN e + e - colliding beam experimental halls may be divided into two parts. The first step is to construct two test-experimental halls associated with the 6.5 GeV x 6.5 GeV e + e - accumulator ring, and the second step is to build four experimental halls at the 30 GeV x 30 GeV e + e - TRISTAN main ring. At this workshop, extensive discussions on the detailed design of the four main ring experimental halls have been made. Four experimental areas will be built at the main ring, and two test-experimental halls at the accumulating ring. Among the four areas at the main ring, two will be used for electron-proton possible as well as electron-positron colliding beam experiment. The other two will be used exclusively for e + e - colliding experiments. Only a preliminary design has been made for these four experimental areas. A tentative plan of a larger experimental hall includes a counting and data processing room, a utility room, and a radiation safety control room. Two smaller halls have simpler structure. The figures of the experimental halls are presented. The two test-experimental halls at the accumulator ring will be used to test the detectors for e + e - colliding experiments before the final installation. The utility rooms designed for the halls are used to supply coolant and electric power of superconducting magnets. At the workshop, various ideas concerning the preliminary plan are presented. (Kato, T.)
The quantum Hall effect helicity
Energy Technology Data Exchange (ETDEWEB)
Shrivastava, Keshav N., E-mail: keshav1001@yahoo.com [Department of Physics, University of Malaya, Kuala Lumpur 50603 (Malaysia); School of Physics, University of Hyderabad, Hyderabad 500046 (India)
2015-04-16
The quantum Hall effect in semiconductor heterostructures is explained by two signs in the angular momentum j=l±s and g=(2j+1)/(2l+1) along with the Landau factor (n+1/2). These modifications in the existing theories explain all of the fractional charges. The helicity which is the sign of the product of the linear momentum with the spin p.s plays an important role for the understanding of the data at high magnetic fields. In particular it is found that particles with positive sign in the spin move in one direction and those with negative sign move in another direction which explains the up and down stream motion of the particles.
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.
The fractional quantum Hall effect
International Nuclear Information System (INIS)
Stormer, H.L.
1988-01-01
The fractional quantum Hall effect (FQHE), is the manifestation of a new, highly correlated, many-particle ground state that forms in a two-dimensional electron system at low temperatures and in high magnetic fields. It is an example of the new physics that has grown out of the tremendous recent advances in semiconductor material science, which has provided us with high-quality, lower-dimensional carrier systems. The novel electronic state exposes itself in transport experiments through quantization of the Hall resistance to an exact rational fraction of h/e, and concomitantly vanishing longitudinal resistivity. Its relevant energy scale is only a few degrees kelvin. The quantization is a consequence of the spontaneous formation of an energy gap separating the condensed ground state from its rather elusive quasiparticle excitations. The theoretical understanding of the novel quantum liquids which underlie the FQHE has predominantly emerged from an ingenious many-particle wave function strongly supported by numerous few-particle simulations. Theory has now constructed a complex model for ideal two-dimensional electron systems in the presence of high magnetic fields and makes definitive, often fascinating predictions. Experiments have successively uncovered odd-denominator fractional states reaching presently to 7/13. The application of new experimental tools to the FQHE, such as optics, microwaves, and phonon techniques promises the direct observation of such parameters as the gap energy and possibly even some of the more elusive quantities in the future. While theory and experiment in the FQHE appear to be converging, there remains considerable room for challenging surprises. This paper provides a concise overview of the FQHE. It focuses on the experimental aspects and states, but does not expand on the theoretical advances. 70 refs., 11 figs
The quantum Hall effects: Philosophical approach
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.
Quantized Hall conductance as a topological invariant
International Nuclear Information System (INIS)
Niu, Q.; Thouless, Ds.J.; Wu, Y.S.
1984-10-01
Whenever the Fermi level lies in a gap (or mobility gap) the bulk Hall conductance can be expressed in a topologically invariant form showing the quantization explicitly. The new formulation generalizes the earlier result by TKNN to the situation where many body interaction and substrate disorder are also present. When applying to the fractional quantized Hall effect we draw the conclusion that there must be a symmetry breaking in the many body ground state. The possibility of writing the fractionally quantized Hall conductance as a topological invariant is also carefully discussed. 19 references
Piezo Voltage Controlled Planar Hall Effect Devices.
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.
Contribution of the study of the Hall Effect. Hall Effect of powder products
International Nuclear Information System (INIS)
Cherville, Jean
1961-01-01
This research thesis reports the development of an apparatus aimed at measuring the Hall Effect and the magneto-resistance of powders at room temperature and at the liquid nitrogen temperature. The author also proposes a theoretical contribution to the Hall Effect and reports the calculation of conditions to be met to obtain a correct value for the Hall constant. Results are experimentally verified. The method is then applied to the study of a set of powdered pre-graphitic graphites. The author shows that their Hall coefficient confirms the model already proposed by Mrozowski. The study of the Hall Effect of any kind of powders can thus be performed, and the Hall Effect can therefore be a mean to study mineral and organic compounds, and notably powdered biological molecules [fr
The infrared Hall effect in YBCO: Temperature and frequency dependence of Hall scattering
International Nuclear Information System (INIS)
Grayson, M.; Cerne, J.; Drew, H.D.; Schmadel, D.C.; Hughes, R.; Preston, J.S.; Kung, P.J.; Vale, L.
1999-01-01
The authors measure the Hall angle, θ H , in YBCO films in the far- and mid-infrared to determine the temperature and frequency dependence of the Hall scattering. Using novel modulation techniques they measure both the Faraday rotation and ellipticity induced by these films in high magnetic fields to deduce the complex conductivity tensor. They observe a strong temperature dependence of the mid-infrared Hall conductivity in sharp contrast to the weak dependence of the longitudinal conductivity. By fitting the frequency dependent normal state Hall angle to a Lorentzian θ H (ω) = ω H /(γ H minus iω) they find the Hall frequency, ω H , is nearly independent of temperature. The Hall scattering rate, γ H , is consistent with γ H ∼ T 2 up to 200 K and is remarkably independent of IR frequency suggesting non-Fermi liquid behavior
Topologically induced fractional Hall steps in the integer quantum Hall regime of MoS 2
Firoz Islam, SK; Benjamin, Colin
2016-09-01
The quantum magnetotransport properties of a monolayer of molybdenum disulfide are derived using linear response theory. In particular, the effect of topological terms on longitudinal and Hall conductivity is analyzed. The Hall conductivity exhibits fractional steps in the integer quantum Hall regime. Further complete spin and valley polarization of the longitudinal conductivitity is seen in presence of these topological terms. Finally, the Shubnikov-de Hass oscillations are suppressed or enhanced contingent on the sign of these topological terms.
How Expectations Do Not Equate with Practice: The Gendered Reality of the Female Resident Assistant
Cousineau, Luc; Chambers, Lori
2015-01-01
Residence hall and house employees (resident assistants) at postsecondary institutions in Canada are an important part of the social and rules-based structure that allows these facilities to operate. These employees are challenged with varied situations that require the application of mediation, authoritarian, recognition, and referral skills. To…
A Study to Identify the Transitional Training Needs for United States Army Medical Residents
1988-07-29
Books Kotler , Philip, and Roberta Clarke. Marketing for Health Care Organizations. Englewood Cliffs: Prentice Hall, 1987. Runyon, Richard P., and...8217 and most can benefit from instruction in administrative principles and practices during residency" (444). A focus began to turn toward residency...leadership development, office communi-ations, professional and legal obligations, Rawls 8 and practice marketing . Because these newly trained physicians
Spin Hall effect by surface roughness
Zhou, Lingjun; Grigoryan, Vahram L.; Maekawa, Sadamichi; Wang, Xuhui; Xiao, Jiang
2015-01-01
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.
Mesoscopic effects in the quantum Hall regime
Indian Academy of Sciences (India)
. 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 ...
Plasmon Geometric Phase and Plasmon Hall Shift
Shi, Li-kun; Song, Justin C. W.
2018-04-01
The collective plasmonic modes of a metal comprise a simple pattern of oscillating charge density that yields enhanced light-matter interaction. Here we unveil that beneath this familiar facade plasmons possess a hidden internal structure that fundamentally alters its dynamics. In particular, we find that metals with nonzero Hall conductivity host plasmons with an intricate current density configuration that sharply departs from that of ordinary zero Hall conductivity metals. This nontrivial internal structure dramatically enriches the dynamics of plasmon propagation, enabling plasmon wave packets to acquire geometric phases as they scatter. At boundaries, these phases accumulate allowing plasmon waves that reflect off to experience a nonreciprocal parallel shift. This plasmon Hall shift, tunable by Hall conductivity as well as plasmon wavelength, displaces the incident and reflected plasmon trajectories and can be readily probed by near-field photonics techniques. Anomalous plasmon geometric phases dramatically enrich the nanophotonics toolbox, and yield radical new means for directing plasmonic beams.
A system for pulse Hall effect measurements
International Nuclear Information System (INIS)
Orzechowski, T.; Kupczak, R.
1975-01-01
Measuring system for fast Hall-voltage changes in an n-type germanium sample irradiated at liquid nitrogen temperature with a high-energy electron-beam from the Van de Graaff accelerator is described. (author)
Novel optical probe for quantum Hall system
Indian Academy of Sciences (India)
to explore Landau levels of a two-dimensional electron gas (2DEG) in modulation doped ... Keywords. Surface photovoltage spectroscopy; quantum Hall effect; Landau levels; edge states. ... An optical fibre carries light from tunable diode laser.
AA under construction in its hall
CERN PhotoLab
1980-01-01
The Antiproton Accumulator was installed in a specially built hall. Here we see it at an "early" stage of installation, just a few magnets on the floor, no vacuum chamber at all, but: 3 months later there was circulating beam !
Elementary theory of quantum Hall effect
Directory of Open Access Journals (Sweden)
Keshav N. Shrivastava
2008-04-01
Full Text Available The Hall effect is the generation of a current perpendicular to both the direction of the applied electric as well as magnetic field in a metal or in a semiconductor. It is used to determine the concentration of electrons. The quantum Hall effect with integer quantization was discovered by von Klitzing and fractionally charged states were found by Tsui, Stormer and Gossard. Robert Laughlin explained the quantization of Hall current by using “flux quantization” and introduced incompressibility to obtain the fractional charge. We have developed the theory of the quantum Hall effect by using the theory of angular momentum. Our predicted fractions are in accord with those measured. We emphasize our explanation of the observed phenomena. We use spin to explain the fractional charge and hence we discover spin-charge locking.
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.
Resistive Instabilities in Hall Current Plasma Discharge
International Nuclear Information System (INIS)
Litvak, Andrei A.; Fisch, Nathaniel J.
2000-01-01
Plasma perturbations in the acceleration channel of a Hall thruster are found to be unstable in the presence of collisions. Both electrostatic lower-hybrid waves and electromagnetic Alfven waves transverse to the applied electric and magnetic field are found to be unstable due to collisions in the E X B electron flow. These results are obtained assuming a two-fluid hydrodynamic model in slab geometry. The characteristic frequencies of these modes are consistent with experimental observations in Hall current plasma thrusters
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.
Fractional statistics and fractional quantized Hall effect
International Nuclear Information System (INIS)
Tao, R.; Wu, Y.S.
1985-01-01
The authors suggest that the origin of the odd-denominator rule observed in the fractional quantized Hall effect (FQHE) may lie in fractional statistics which govern quasiparticles in FQHE. A theorem concerning statistics of clusters of quasiparticles implies that fractional statistics do not allow coexistence of a large number of quasiparticles at fillings with an even denominator. Thus, no Hall plateau can be formed at these fillings, regardless of the presence of an energy gap. 15 references
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.
A review of the quantum Hall effects in MgZnO/ZnO heterostructures
Falson, Joseph; Kawasaki, Masashi
2018-05-01
This review visits recent experimental efforts on high mobility two-dimensional electron systems (2DES) hosted at the Mg x Zn1-x O/ZnO heterointerface. We begin with the growth of these samples, and highlight the key characteristics of ozone-assisted molecular beam epitaxy required for their production. The transport characteristics of these structures are found to rival that of traditional semiconductor material systems, as signified by the high electron mobility (μ > 1000 000 cm2 Vs‑1) and rich quantum Hall features. Owing to a large effective mass and small dielectric constant, interaction effects are an order of magnitude stronger in comparison with the well studied GaAs-based 2DES. The strong correlation physics results in robust Fermi-liquid renormalization of the effective mass and spin susceptibility of carriers, which in turn dictates the parameter space for the quantum Hall effect. Finally, we explore the quantum Hall effect with a particular emphasis on the spin degree of freedom of carriers, and how their large spin splitting allows control of the ground states encountered at ultra-low temperatures within the fractional quantum Hall regime. We discuss in detail the physics of even-denominator fractional quantum Hall states, whose observation and underlying character remain elusive and exotic.
75 FR 22770 - Gary E. Hall and Rita Hall; Notice of Availability of Environmental Assessment
2010-04-30
... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Project No. 13652-000-Montana] 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, and the Federal Energy Regulatory...
Charge carrier coherence and Hall effect in organic semiconductors
Yi, H. T.; Gartstein, Y. N.; Podzorov, V.
2016-01-01
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. PMID:27025354
Charge carrier coherence and Hall effect in organic semiconductors.
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.
Zenhong, C.; Buwalda, P.L.
2011-01-01
Chinese dumplings such as Jiao Zi and Bao Zi are two of the popular traditional foods in Asia. They are usually made from wheat flour dough (rice flour or starch is sometimes used) that contains fillings. They can be steamed, boiled and fried and are consumed either as a main meal or dessert. As
Reed, Kathlyn L
2005-01-01
Herbert James Hall, MD (1870-1923), was a pioneer in the systematic and organized study of occupation as therapy for persons with nervous and mental disorders that he called the "work cure." He began his work in 1904 during the early years of the Arts and Crafts Movement in the United States. His primary interest was the disorder neurasthenia, a condition with many symptoms including chronic fatigue, stress, and inability to work or perform everyday tasks. The prevailing treatment of the day was absolute bed rest known as the "rest cure." Hall believed that neurasthenia was not caused by overwork but by faulty living habits that could be corrected through an ordered life schedule and selected occupations. He identified several principles of therapy that are still used today including graded activity and energy conservation. Dr. Adolph Meyer credits Hall for organizing the ideas on the therapeutic use of occupation (Meyer, 1922). Hall also provided the name American Occupational Therapy Association for the professional organization and served as the fourth president. For his many contributions to the profession Hall deserves to be recognized as a major contributor to the development and organization of occupational therapy.
A new CMOS Hall angular position sensor
Energy Technology Data Exchange (ETDEWEB)
Popovic, R.S.; Drljaca, P. [Swiss Federal Inst. of Tech., Lausanne (Switzerland); Schott, C.; Racz, R. [SENTRON AG, Zug (Switzerland)
2001-06-01
The new angular position sensor consists of a combination of a permanent magnet attached to a shaft and of a two-axis magnetic sensor. The permanent magnet produces a magnetic field parallel with the magnetic sensor plane. As the shaft rotates, the magnetic field also rotates. The magnetic sensor is an integrated combination of a CMOS Hall integrated circuit and a thin ferromagnetic disk. The CMOS part of the system contains two or more conventional Hall devices positioned under the periphery of the disk. The ferromagnetic disk converts locally a magnetic field parallel with the chip surface into a field perpendicular to the chip surface. Therefore, a conventional Hall element can detect an external magnetic field parallel with the chip surface. As the direction of the external magnetic field rotates in the chip plane, the output voltage of the Hall element varies as the cosine of the rotation angle. By placing the Hall elements at the appropriate places under the disk periphery, we may obtain the cosine signals shifted by 90 , 120 , or by any other angle. (orig.)
Composite fermions in the quantum Hall effect
International Nuclear Information System (INIS)
Johnson, B.L.; Kirczenow, G.
1997-01-01
The quantum Hall effect and associated quantum transport phenomena in low-dimensional systems have been the focus of much attention for more than a decade. Recent theoretical development of interesting quasiparticles - 'composite fermions' - has led to significant advances in understanding and predicting the behaviour of two-dimensional electron systems under high transverse magnetic fields. Composite fermions may be viewed as fermions carrying attached (fictitious) magnetic flux. Here we review models of the integer and fractional quantum Hall effects, including the development of a unified picture of the integer and fractional effects based upon composite fermions. The composite fermion picture predicts remarkable new physics: the formation of a Fermi surface at high magnetic fields, and anomalous ballistic transport, thermopower, and surface acoustic wave behaviour. The specific theoretical predictions of the model, as well as the body of experimental evidence for these phenomena are reviewed. We also review recent edge-state models for magnetotransport in low-dimensional devices based on the composite fermion picture. These models explain the fractional quantum Hall effect and transport phenomena in nanoscale devices in a unified framework that also includes edge state models of the integer quantum Hall effect. The features of the composite fermion edge-state model are compared and contrasted with those of other recent edge-state models of the fractional quantum Hall effect. (author)
Air temperature gradient in large industrial hall
Karpuk, Michał; Pełech, Aleksander; Przydróżny, Edward; Walaszczyk, Juliusz; Szczęśniak, Sylwia
2017-11-01
In the rooms with dominant sensible heat load, volume airflow depends on many factors incl. pre-established temperature difference between exhaust and supply airflow. As the temperature difference is getting higher, airflow volume drops down, consequently, the cost of AHU is reduced. In high industrial halls with air exhaust grids located under the ceiling additional temperature gradient above working zone should be taken into consideration. In this regard, experimental research of the vertical air temperature gradient in high industrial halls were carried out for the case of mixing ventilation system The paper presents the results of air temperature distribution measurements in high technological hall (mechanically ventilated) under significant sensible heat load conditions. The supply airflow was delivered to the hall with the help of the swirl diffusers while exhaust grids were located under the hall ceiling. Basing on the air temperature distribution measurements performed on the seven pre-established levels, air temperature gradient in the area between 2.0 and 7.0 m above the floor was calculated and analysed.
Field theory approach to quantum hall effect
International Nuclear Information System (INIS)
Cabo, A.; Chaichian, M.
1990-07-01
The Fradkin's formulation of statistical field theory is applied to the Coulomb interacting electron gas in a magnetic field. The electrons are confined to a plane in normal 3D-space and also interact with the physical 3D-electromagnetic field. The magnetic translation group (MTG) Ward identities are derived. Using them it is shown that the exact electron propagator is diagonalized in the basis of the wave functions of the free electron in a magnetic field whenever the MTG is unbroken. The general tensor structure of the polarization operator is obtained and used to show that the Chern-Simons action always describes the Hall effect properties of the system. A general proof of the Streda formula for the Hall conductivity is presented. It follows that the coefficient of the Chern-Simons terms in the long-wavelength approximation is exactly given by this relation. Such a formula, expressing the Hall conductivity as a simple derivative, in combination with diagonal form of the full propagator allows to obtain a simple expressions for the filling factor and the Hall conductivity. Indeed, these results, after assuming that the chemical potential lies in a gap of the density of states, lead to the conclusion that the Hall conductivity is given without corrections by σ xy = νe 2 /h where ν is the filling factor. In addition it follows that the filling factor is independent of the magnetic field if the chemical potential remains in the gap. (author). 21 ref, 1 fig
Extrinsic spin Hall effect in graphene
Rappoport, Tatiana
The intrinsic spin-orbit coupling in graphene is extremely weak, making it a promising spin conductor for spintronic devices. In addition, many applications also require the generation of spin currents in graphene. Theoretical predictions and recent experimental results suggest one can engineer the spin Hall effect in graphene by greatly enhancing the spin-orbit coupling in the vicinity of an impurity. The extrinsic spin Hall effect then results from the spin-dependent skew scattering of electrons by impurities in the presence of spin-orbit interaction. This effect can be used to efficiently convert charge currents into spin-polarized currents. I will discuss recent experimental results on spin Hall effect in graphene decorated with adatoms and metallic cluster and show that a large spin Hall effect can appear due to skew scattering. While this spin-orbit coupling is small if compared with what it is found in metals, the effect is strongly enhanced in the presence of resonant scattering, giving rise to robust spin Hall angles. I will present our single impurity scattering calculations done with exact partial-wave expansions and complement the analysis with numerical results from a novel real-space implementation of the Kubo formalism for tight-binding Hamiltonians. The author acknowledges the Brazilian agencies CNPq, CAPES, FAPERJ and INCT de Nanoestruturas de Carbono for financial support.
Noodles, traditionally and today
Directory of Open Access Journals (Sweden)
Na Zhang
2016-09-01
Full Text Available Chinese noodles originated in the Han dynasty, which has more than 4,000 years of history. There are many stories about the origin of noodles. To a certain extent, noodles also reflect the cultural traditions and customs of China, which essentially means “human nature” and “worldly common sense”. There are thousands of varieties of noodles in China, according to the classification of the shape of noodles, seasoning gravy, cooking craft, and so on. Many noodles have local characteristics. Noodles are accepted by people from all over the world. The industrial revolution and the development of the food industry realized the transition from a traditional handicraft industry to mass production using machinery. In addition, the invention of instant noodles and their mass production also greatly changed the noodle industry. In essence, noodles are a kind of cereal food, which is the main body of the traditional Chinese diet. It is the main source of energy for Chinese people and the most economical energy food. Adhering to the principle of “making cereal food the main food”, is to maintain our Chinese good diet tradition, which can avoid the disadvantages of a high energy, high fat, and low carbohydrate diet, and promote health. The importance of the status of noodles in the dietary structure of residents in our country and the health impact should not be ignored.
Localization in a quantum spin Hall system.
Onoda, Masaru; Avishai, Yshai; Nagaosa, Naoto
2007-02-16
The localization problem of electronic states in a two-dimensional quantum spin Hall system (that is, a symplectic ensemble with topological term) is studied by the transfer matrix method. The phase diagram in the plane of energy and disorder strength is exposed, and demonstrates "levitation" and "pair annihilation" of the domains of extended states analogous to that of the integer quantum Hall system. The critical exponent nu for the divergence of the localization length is estimated as nu congruent with 1.6, which is distinct from both exponents pertaining to the conventional symplectic and the unitary quantum Hall systems. Our analysis strongly suggests a different universality class related to the topology of the pertinent system.
Hall probe magnetometer for SSC magnet cables
International Nuclear Information System (INIS)
Cross, R.W.; Goldfarb, R.B.
1991-01-01
The authors of this paper constructed a Hall probe magnetometer to measure the magnetization hysteresis loops of Superconducting Super Collider magnet cables. The instrument uses two Hall-effect field sensors to measure the applied field H and the magnetic induction B. Magnetization M is calculated from the difference of the two quantities. The Hall probes are centered coaxially in the bore of a superconducting solenoid with the B probe against the sample's broad surface. An alternative probe arrangement, in which M is measured directly, aligns the sample probe parallel to the field. The authors measured M as a function of H and field cycle rate both with and without a dc transport current. Flux creep as a function of current was measured from the dependence of ac loss on the cycling rate and from the decay of magnetization with time. Transport currents up to 20% of the critical current have minimal effect on magnetization and flux creep
Spin Hall Effect in Doped Semiconductor Structures
Tse, Wang-Kong; Das Sarma, Sankar
2006-03-01
We present a microscopic theory of the extrinsic spin Hall effect based on the diagrammatic perturbation theory. Side-jump (SJ) and skew-scattering (SS) contributions are explicitly taken into account to calculate the spin Hall conductivity, and we show their effects scale as σxy^SJ/σxy^SS ˜(/τ)/ɛF, where τ being the transport relaxation time. Motivated by recent experimental work we apply our theory to n-doped and p-doped 3D and 2D GaAs structures, obtaining analytical formulas for the SJ and SS contributions. Moreover, the ratio of the spin Hall conductivity to longitudinal conductivity is found as σs/σc˜10-3-10-4, in reasonable agreement with the recent experimental results of Kato et al. [Science 306, 1910 (2004)] in n-doped 3D GaAs system.
Shielding consideration for the SSCL experimental halls
International Nuclear Information System (INIS)
Bull, J.; Coyne, J.; Mokhov, N.; Stapleton, G.
1994-03-01
The Superconducting Super Collider which is being designed and built in Waxahachie, Texas consists Of series of proton accelerators, culminating in a 20 Te proton on proton collider. The collider will be in a tunnel which will be 87 km in circumference and. on average about 30 meters underground. The present design calls for two large interaction halls on the east side of the ring. The shielding for these halls is being designed for an interaction rate of 10 9 Hz or 10 16 interactions per year, based on 10 7 seconds per operational year. SSC guidelines require that the shielding be designed to meet the criterion of 1mSv per year for open areas off site 2mSv per year for open areas on site, and 2mSv per year for controlled areas. Only radiation workers will be routinely allowed to work in controlled areas. It should be pointed that there is a potential for an accidental full beam loss in either of the experimental halls, and this event would consist of the loss of the full circulating beam up to 4 x 10 14 protons. With the present design. the calculated dose equivalent for this event is about 10% of the annual dose equivalent for the normal p-p interactions, so that die accident condition does not control the shielding. If, for instance, local shielding within the experimental hall is introduced into the calculations, this could change. The shielding requirements presented here are controlled by the normal p-p interactions. Three important questions were addressed in the present calculations. They are (1) the thickness of the roof over the experimental halls, (2) the configuration of the shafts and adits which give access to the halls, and (3) the problem of ground water and air activation
Developments in Scanning Hall Probe Microscopy
Chouinard, Taras; Chu, Ricky; David, Nigel; Broun, David
2009-05-01
Low temperature scanning Hall probe microscopy is a sensitive means of imaging magnetic structures with high spatial resolution and magnetic flux sensitivity approaching that of a Superconducting Quantum Interference Device. We have developed a scanning Hall probe microscope with novel features, including highly reliable coarse positioning, in situ optimization of sensor-sample alignment and capacitive transducers for linear, long range positioning measurement. This has been motivated by the need to reposition accurately above fabricated nanostructures such as small superconducting rings. Details of the design and performance will be presented as well as recent progress towards time-resolved measurements with sub nanosecond resolution.
Enhanced Performance of Cylindrical Hall Thrusters
International Nuclear Information System (INIS)
Raitses, Y.; Smirnov, A.; Fisch, N.J.
2007-01-01
The cylindrical thruster differs significantly in its underlying physical mechanisms from the conventional annular Hall thruster. It features high ionization efficiency, quiet operation, ion acceleration in a large volume-to-surface ratio channel, and performance comparable with the state-of-the-art conventional Hall thrusters. Very significant plume narrowing, accompanied by the increase of the energetic ion fraction and improvement of ion focusing, led to 50-60% increase of the thruster anode efficiency. These improvements were achieved by overrunning the discharge current in the magnetized thruster plasma
Inverse spin Hall effect by spin injection
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.
Prototype dining hall energy efficiency study
Energy Technology Data Exchange (ETDEWEB)
Mazzucchi, R.P.; Bailey, S.A.; Zimmerman, P.W.
1988-06-01
The energy consumption of food service facilities is among the highest of any commercial building type, owing to the special requirements for food preparation, sanitation, and ventilation. Consequently, the US Air Force Engineering and Services Center (AFESC) contracted with Pacific Northwest Laboratory (PNL) to collect and analyze end-use energy consumption data for a prototypical dining hall and make specific recommendations on cost-effective energy conservation options. This information will be used to establish or update criteria for dining hall designs and retrofits as appropriate. 6 refs., 21 figs., 23 tabs.
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...
International Nuclear Information System (INIS)
Jager, K. de
2003-01-01
Proton knock-out is studied in a broad program in Hall A at Jefferson Lab. The first experiment performed in Hall A studied the 16 O(e,e'p) reaction. Since then proton knock-out experiments have studied a variety of aspects of that reaction, from single-nucleon properties to its mechanism, such as final-state interactions and two-body currents, in nuclei from 2 H to 16 O. In this review the accomplishments of this program will be summarized and an outlook given of expected future results. (orig.)
Theory of fractional quantum Hall effect
International Nuclear Information System (INIS)
Kostadinov, I.Z.
1984-09-01
A theory of the fractional quantum Hall effect is constructed by introducing 3-particle interactions breaking the symmetry for ν=1/3 according to a degeneracy theorem proved here. An order parameter is introduced and a gap in the single particle spectrum is found. The critical temperature, critical filling number and critical behaviour are determined as well as the Ginzburg-Landau equation coefficients. A first principle calculation of the Hall current is given. 3, 5, 7 electron tunneling and Josephson interference effects are predicted. (author)
Bound values for Hall conductivity of heterogeneous medium under ...
Indian Academy of Sciences (India)
- ditions 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 ...
Sugiyama, Shigeru
2006-01-01
The commercialization of drugs started toward the end of Heian period (794-1192) when not only aristocrats and monks who were traditional patrons to drug makers, but also local clans and landlords who became powerful as a result of the disbanding of aristocratic manors accumulated enough wealth to spend money on medicine. Although traveling around the country was still a dangerous endeavor, merchants assembled groups to bring lucrative foreign drugs (mainly Chinese) to remote areas. The spread of commercial drugs to common people, however, did not happen until the early Edo period (1603-1867), when the so-called barrier system was installed nationwide to make domestic travel safe. Commercialization started in large cities and gradually spread to other areas. Many nostrums popular until recently appeared in the Genroku period (1688-1703) or later. Many such nostrums were all-cures, often consisting of such active ingredients as Saussureae radix, Agalloch, or Gambir. Even in the Edo period, many people living in agricultural or fishing villages, as well as those in the lower tier, were still poor. Much of the medication available to those people was therefore made of various plant or animal-derived substances that were traditionally used as folk medicines.
June 1992 Hall B collaboation meeting
International Nuclear Information System (INIS)
Dennis, L.
1992-01-01
The Hall B collaboration meeting at the CEBAF 1992 Summer Workshop consisted of technical and physics working group meetings, a special beam line devices working group meeting the first meeting of the membership committee, a technical representatives meeting and a full collaboration meeting. Highlights of these meetings are presented in this report
Chapin Hall Projects and Publications. Autumn 1999.
Chicago Univ., IL. Chapin Hall Center for Children.
This guide chronicles the ongoing work and writings of the Chapin Hall Center for Children at the University of Chicago, a policy research center dedicated to bringing sound information, rigorous analyses, innovative ideas, and an independent, multidisciplinary perspective to bear on policies and programs affecting children. This guide, organized…
Quantum Hall Conductivity and Topological Invariants
Reyes, Andres
2001-04-01
A short survey of the theory of the Quantum Hall effect is given emphasizing topological aspects of the quantization of the conductivity and showing how topological invariants can be derived from the hamiltonian. We express these invariants in terms of Chern numbers and show in precise mathematical terms how this relates to the Kubo formula.
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...
Pseudospin anisotropy classification of quantum Hall ferromagnets
Czech Academy of Sciences Publication Activity Database
Jungwirth, Tomáš; MacDonald, A. H.
2000-01-01
Roč. 63, č. 3 (2000), s. 035305-1 - 035305-9 ISSN 0163-1829 R&D Projects: GA ČR GA202/98/0085 Institutional research plan: CEZ:AV0Z1010914 Keywords : quantum Hall ferromagnets * anisotropy Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.065, year: 2000
Anomalous Hall effect in disordered multiband metals
Czech Academy of Sciences Publication Activity Database
Kovalev, A.A.; Sinova, Jairo; Tserkovnyak, Y.
2010-01-01
Roč. 105, č. 3 (2010), 036601/1-036601/4 ISSN 0031-9007 Institutional research plan: CEZ:AV0Z10100521 Keywords : anomalous Hall effect * spintronics Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 7.621, year: 2010
Anomalous Hall conductivity: Local orbitals approach
Czech Academy of Sciences Publication Activity Database
Středa, Pavel
2010-01-01
Roč. 82, č. 4 (2010), 045115/1-045115/9 ISSN 1098-0121 Institutional research plan: CEZ:AV0Z10100521 Keywords : anomalous Hall effect * Berry phase correction * orbital polarization momentum Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.772, year: 2010
Quantization and hall effect: necessities and difficulties
International Nuclear Information System (INIS)
Ahmed Bouketir; Hishamuddin Zainuddin
1999-01-01
The quantization procedure is a necessary tool for a proper understanding of many interesting quantum phenomena in modern physics. In this note, we focus on geometrical framework for such procedures, particularly the group-theoretic approach and their difficulties. Finally we look through the example of Hall effect as a quantized macroscopic phenomenon with group-theoretic quantization approach. (author)
Spin Hall effect on a noncommutative space
International Nuclear Information System (INIS)
Ma Kai; Dulat, Sayipjamal
2011-01-01
We study the spin-orbital interaction and the spin Hall effect of an electron moving on a noncommutative space under the influence of a vector potential A(vector sign). On a noncommutative space, we find that the commutator between the vector potential A(vector sign) and the electric potential V 1 (r(vector sign)) of the lattice induces a new term, which can be treated as an effective electric field, and the spin Hall conductivity obtains some correction. On a noncommutative space, the spin current and spin Hall conductivity have distinct values in different directions, and depend explicitly on the noncommutative parameter. Once this spin Hall conductivity in different directions can be measured experimentally with a high level of accuracy, the data can then be used to impose bounds on the value of the space noncommutativity parameter. We have also defined a new parameter, σ=ρθ (ρ is the electron concentration, θ is the noncommutativity parameter), which can be measured experimentally. Our approach is based on the Foldy-Wouthuysen transformation, which gives a general Hamiltonian of a nonrelativistic electron moving on a noncommutative space.
Curricula and Organization of Primary Care Residencies in Internal Medicine.
Eisenberg, John M.
1980-01-01
The organization and curricula of internal medicine residencies programs that emphasize primary care are described and compared with traditional residencies in internal medicine. It is noted that primary care residents spend more time in ambulatory care and are allowed more electives in specialties outside of internal medicine. Out-of-hospital…
The Effectiveness of Hypermedia Instructional Modules for Radiology Residents.
Shaw, Steven G.; And Others
1995-01-01
Details the development and field testing of hypermedia training materials for teaching radiology residents at the Montreal General Hospital (Canada). Compares results of randomly teaching 24 residents with either hypermedia or traditional classroom methods. Results indicate that residents who learned with hypermedia generally performed as well as…
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.
Pearson, Helen
2013-01-01
Stephen Hall, a freelance science writer and science-communication teacher, received the Walter Sullivan Award for Excellence in Science Journalism-Features at the AGU Fall Meeting Honors Ceremony, held on 5 December 2012 in San Francisco, Calif. Hall was honored for the article "At Fault?" published 15 September 2011 in Nature. The article examines the legal, personal, and political repercussions from a 2009 earthquake in L'Aquila, Italy for seismologists who had attempted to convey seismic risk assessments to the public. The 6.3 magnitude quake devastated the medieval town and caused more than 300 deaths. Six scientists and one government official were subsequently convicted of manslaughter and sentenced to prison for inadequately assessing and mischaracterizing the risks to city residents, despite the inexact nature of seismic risk assessment. The Sullivan award is for work published with a deadline pressure of more than 1 week.
Digital technology impacts on the Arnhem transfer hall structural design
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
Magnetoresistance in quantum Hall metals due to Pancharatnam ...
Indian Academy of Sciences (India)
Abstract. We derive the trial Hall resistance formula for the quantum Hall metals to address both the integer and fractional quantum Hall effects. Within the degenerate (and crossed) Landau levels, and in the presence of changing magnetic field strength, one can invoke two physical processes responsible for the electron ...
Destruction of the fractional quantum Hall effect by disorder
International Nuclear Information System (INIS)
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
A Hall probe technique for characterizing high-temperature superconductors
International Nuclear Information System (INIS)
Zhang, J.; Sheldon, P.; Ahrenkiel, R.K.
1992-01-01
Thin-film GaAs Hall probes were fabricated by molecular beam epitaxy technology. A contactless technique was developed to characterize thin-film, high-temperature superconducting (HTSC) materials. The Hall probes detected the ac magnetic flux penetration through the high-temperature superconducting materials. The Hall detector has advantages over the mutual inductance magnetic flux detector
Spin-singlet hierarchy in the fractional quantum Hall effect
Ino, Kazusumi
1999-01-01
We show that the so-called permanent quantum Hall states are formed by the integer quantum Hall effects on the Haldane-Rezayi quantum Hall state. Novel conformal field theory description along with this picture is deduced. The odd denominator plateaux observed around $\
A Redundancy Mechanism Design for Hall-Based Electronic Current Transformers
Directory of Open Access Journals (Sweden)
Kun-Long Chen
2017-03-01
Full Text Available Traditional current transformers (CTs suffer from DC and AC saturation and remanent magnetization in many industrial applications. Moreover, the drawbacks of traditional CTs, such as closed iron cores, bulky volume, and heavy weight, further limit the development of an intelligent power protection system. In order to compensate for these drawbacks, we proposed a novel current measurement method by using Hall sensors, which is called the Hall-effect current transformer (HCT. The existing commercial Hall sensors are electronic components, so the reliability of the HCT is normally worse than that of the traditional CT. Therefore, our study proposes a redundancy mechanism for the HCT to strengthen its reliability. With multiple sensor modules, the method has the ability to improve the accuracy of the HCT as well. Additionally, the proposed redundancy mechanism monitoring system provides a condition-based maintenance for the HCT. We verify our method with both simulations and an experimental test. The results demonstrate that the proposed HCT with a redundancy mechanism can almost achieve Class 0.2 for measuring CTs according to IEC Standard 60044-8.
Department of Veterans Affairs — The Residency Allocation Database is used to determine allocation of funds for residency programs offered by Veterans Affairs Medical Centers (VAMCs). Information...
Energy Technology Data Exchange (ETDEWEB)
Owerre, S. A., E-mail: solomon@aims.ac.za [African Institute for Mathematical Sciences, 6 Melrose Road, Muizenberg, Cape Town 7945, South Africa and Perimeter Institute for Theoretical Physics, 31 Caroline St. N., Waterloo, Ontario N2L 2Y5 (Canada)
2016-07-28
Quite recently, the magnon Hall effect of spin excitations has been observed experimentally on the kagome and pyrochlore lattices. The thermal Hall conductivity κ{sup xy} changes sign as a function of magnetic field or temperature on the kagome lattice, and κ{sup xy} 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 κ{sup xy} 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 T{sup 2} 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.
A simulation Model of the Reactor Hall Ventilation and air Conditioning Systems of ETRR-2
International Nuclear Information System (INIS)
Abd El-Rahman, M.F.
2004-01-01
Although the conceptual design for any system differs from one designer to another. each of them aims to achieve the function of the system required. the ventilation and air conditioning system of reactors hall is one of those systems that really differs but always dose its function for which it is designed. thus, ventilation and air conditioning in some reactor hall constitute only one system whereas in some other ones, they are separate systems. the Egypt Research Reactor-2 (ETRR-2)represents the second type. most studies conducted on ventilation and air conditioning simulation models either in traditional building or for research rectors show that those models were not designed similarly to the model of the hall of ETRR-2 in which ventilation and air conditioning constitute two separate systems.besides, those studies experimented on ventilation and air conditioning simulation models of reactor building predict the temperature and humidity inside these buildings at certain outside condition and it is difficult to predict when the outside conditions are changed . also those studies do not discuss the influences of reactor power changes. therefore, the present work deals with a computational study backed by infield experimental measurements of the performance of the ventilation and air conditioning systems of reactor hall during normal operation at different outside conditions as well as at different levels of reactor power
Diagnostics Systems for Permanent Hall Thrusters Development
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
Valley-chiral quantum Hall state in graphene superlattice structure
Tian, H. Y.; Tao, W. W.; Wang, J.; Cui, Y. H.; Xu, N.; Huang, B. B.; Luo, G. X.; Hao, Y. H.
2016-05-01
We theoretically investigate the quantum Hall effect in a graphene superlattice (GS) system, in which the two valleys of graphene are coupled together. In the presence of a perpendicular magnetic field, an ordinary quantum Hall effect is found with the sequence σxy=ν e^2/h(ν=0,+/-1,+/-2,\\cdots) . At the zeroth Hall platform, a valley-chiral Hall state stemming from the single K or K' valley is found and it is localized only on one sample boundary contributing to the longitudinal conductance but not to the Hall conductivity. Our findings may shed light on the graphene-based valleytronics applications.
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...... be extracted from micro four-point measurements performed on a rectangular pad. The dimension of the investigated pad is 400 Ã— 430 Â¿m2, and the probe pitches range from 20 Â¿m to 50 Â¿m. The Monte Carlo method is used to find the optimal way to perform the Hall measurement and extract Hall mobility most...
Giant photonic Hall effect in magnetophotonic crystals.
Merzlikin, A M; Vinogradov, A P; Inoue, M; Granovsky, A B
2005-10-01
We have considered a simple, square, two-dimensional (2D) PC built of a magneto-optic matrix with square holes. It is shown that using such a magnetophotonic crystal it is possible to deflect a light beam at very large angles by applying a nonzero external magnetic field. The effect is called the giant photonic Hall effect (GPHE) or the magnetic superprism effect. The GPHE is based on magneto-optical properties, as is the photonic Hall effect [B. A. van Tiggelen and G. L. J. A. Rikken, in, edited by V. M. Shalaev (Springer-Verlag, Berlin, 2002), p. 275]; however GPHE is not caused by asymmetrical light scattering but rather by the influence of an external magnetic field on the photonic band structure.
Assessment of elevator rope using Hall Sensor
Energy Technology Data Exchange (ETDEWEB)
Lee, Jong O; Yoon, Woon Ha; Son, Young Ho; Kim, Jung Woo [Korea Institute of Machinery and Materials, Daejeon (Korea, Republic of); Lee, Jong Ku [Pukyung National University, Pusan (Korea, Republic of)
2003-07-01
Defect detection of wire rope for an elevator was investigated through the measurement of magnetic flux leakage. The types of defect usually found in wire rope categorized such as inner and outer wire breakage and wear. The specimens that has artificial defects were magnetized via permanent magnet, and measurement of magnetic flux leakage on the defects was performed with Hall sensor. In wire broken model, a defect smaller than 0.4 mm and 1 mm in depth on outer and inner wire rope, respectively, could be detected well. In wear model, smaller defect could not be detected clearly, however, appearance of changing of total magnetic flux during magnetic pole of the sensor passing through a defect 0.2 mm in depth at 4 mm or above width could make possible to detect it. From the results, the measurement via Hall sensor might be useful tool for defect detection of wire rope.
Assesment of elevator rope using hall sensor
Energy Technology Data Exchange (ETDEWEB)
Lee, Jong O; Yoon, Woon Ha; Son, Young Ho [Korea Institute of Machinery and Materials, Daejeon (Korea, Republic of); Kim, Jung Woo; Lee, Jong Ku [Pukyong National University, Pusan (Korea, Republic of)
2003-05-15
Defect detection of wire rope for an elevator was investigated through the measurement of magnetic flux leakage. The types of defect usually found in wire rope categorized such as inner and outer wire breakage and wear. The specimens that has artificial defects were magnetized via permanent magnet, and measurement of magnetic flux leakage on the defects was performed with Hall sensor. In wire broken model, a defect smaller than 0.4mm and 1mm in depth on outer and inner wire rope, respectively, could be detected well. In wear model, smaller defect could not be detected clearly, however, appearance of changing of total magnetic flux during magnetic pole of the sensor passing through a defect 0.2mm in depth at 4mm or above width could make possible to detect it. From the results, the measurement via Hall sensor might be useful tool for defect detection of wire rope.
Infinite symmetry in the quantum Hall effect
Directory of Open Access Journals (Sweden)
Lütken C.A.
2014-04-01
Full Text Available The new states of matter and concomitant quantum critical phenomena revealed by the quantum Hall effect appear to be accompanied by an emergent modular symmetry. The extreme rigidity of this infinite symmetry makes it easy to falsify, but two decades of experiments have failed to do so, and the location of quantum critical points predicted by the symmetry is in increasingly accurate agreement with scaling experiments. The symmetry severely constrains the structure of the effective quantum field theory that encodes the low energy limit of quantum electrodynamics of 1010 charges in two dirty dimensions. If this is a non-linear σ-model the target space is a torus, rather than the more familiar sphere. One of the simplest toroidal models gives a critical (correlation length exponent that agrees with the value obtained from numerical simulations of the quantum Hall effect.
Stuart Hall and Cultural Studies, circa 1983
Directory of Open Access Journals (Sweden)
Ann Curthoys
2017-11-01
Full Text Available Stuart Hall sought to internationalise theoretical debates and to create Cultural Studies as interdisciplinary. We chart his theoretical journey through a detailed examination of a series of lectures delivered in 1983 and now published for the first time. In these lectures, he discusses theorists such as E.P. Thompson, Raymond Williams, Louis Althusser, Levi Strauss and Antonio Gramsci, and explores the relationship between ideas and social structure, the specificities of class and race, and the legacies of slavery. We note his turn towards metaphors of divergence and dispersal and highlight how autobiographical and deeply personal Hall is in these lectures, especially in his ego histoire moment of traumatic memory recovery.
Hall magnetohydrodynamics: Conservation laws and Lyapunov stability
International Nuclear Information System (INIS)
Holm, D.D.
1987-01-01
Hall electric fields produce circulating mass flow in confined ideal-fluid plasmas. The conservation laws, Hamiltonian structure, equilibrium state relations, and Lyapunov stability conditions are presented here for ideal Hall magnetohydrodynamics (HMHD) in two and three dimensions. The approach here is to use the remarkable array of nonlinear conservation laws for HMHD that follow from its Hamiltonian structure in order to construct explicit Lyapunov functionals for the HMHD equilibrium states. In this way, the Lyapunov stability analysis provides classes of HMHD equilibria that are stable and whose linearized initial-value problems are well posed (in the sense of possessing continuous dependence on initial conditions). Several examples are discussed in both two and three dimensions
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)
Theory of fractional quantum hall effect
International Nuclear Information System (INIS)
Kostadinov, I.Z.
1985-08-01
A theory of the Fractional Quantum Hall Effect is constructed based on magnetic flux fractionization, which lead to instability of the system against selfcompression. A theorem is proved stating that arbitrary potentials fail to lift a specific degeneracy of the Landau level. For the case of 1/3 fractional filling a model 3-particles interaction is constructed breaking the symmetry. The rigid 3-particles wave function plays the role of order parameter. In a BCS type of theory the gap in the single particles spectrum is produced by the 3-particles interaction. The mean field critical behaviour and critical parameters are determined as well as the Ginsburg-Landau equation coefficients. The Hall conductivity is calculated from the first principles and its temperature dependence is found. The simultaneous tunnelling of 3,5,7 etc. electrons and quantum interference effects are predicted. (author)
Coulomb blockade in hierarchical quantum Hall droplets
International Nuclear Information System (INIS)
Cappelli, Andrea; Georgiev, Lachezar S; Zemba, Guillermo R
2009-01-01
The degeneracy of energy levels in a quantum dot of Hall fluid, leading to conductance peaks, can be readily derived from the partition functions of conformal field theory. Their complete expressions can be found for Hall states with both Abelian and non-Abelian statistics, upon adapting known results for the annulus geometry. We analyze the Abelian states with hierarchical filling fractions, ν = m/(mp ± 1), and find a non-trivial pattern of conductance peaks. In particular, each one of them occurs with a characteristic multiplicity, which is due to the extended symmetry of the m-folded edge. Experimental tests of the multiplicity can shed more light on the dynamics of this composite edge. (fast track communication)
Assessment of elevator rope using Hall Sensor
International Nuclear Information System (INIS)
Lee, Jong O; Yoon, Woon Ha; Son, Young Ho; Kim, Jung Woo; Lee, Jong Ku
2003-01-01
Defect detection of wire rope for an elevator was investigated through the measurement of magnetic flux leakage. The types of defect usually found in wire rope categorized such as inner and outer wire breakage and wear. The specimens that has artificial defects were magnetized via permanent magnet, and measurement of magnetic flux leakage on the defects was performed with Hall sensor. In wire broken model, a defect smaller than 0.4 mm and 1 mm in depth on outer and inner wire rope, respectively, could be detected well. In wear model, smaller defect could not be detected clearly, however, appearance of changing of total magnetic flux during magnetic pole of the sensor passing through a defect 0.2 mm in depth at 4 mm or above width could make possible to detect it. From the results, the measurement via Hall sensor might be useful tool for defect detection of wire rope.
Assesment of elevator rope using hall sensor
International Nuclear Information System (INIS)
Lee, Jong O; Yoon, Woon Ha; Son, Young Ho; Kim, Jung Woo; Lee, Jong Ku
2003-01-01
Defect detection of wire rope for an elevator was investigated through the measurement of magnetic flux leakage. The types of defect usually found in wire rope categorized such as inner and outer wire breakage and wear. The specimens that has artificial defects were magnetized via permanent magnet, and measurement of magnetic flux leakage on the defects was performed with Hall sensor. In wire broken model, a defect smaller than 0.4mm and 1mm in depth on outer and inner wire rope, respectively, could be detected well. In wear model, smaller defect could not be detected clearly, however, appearance of changing of total magnetic flux during magnetic pole of the sensor passing through a defect 0.2mm in depth at 4mm or above width could make possible to detect it. From the results, the measurement via Hall sensor might be useful tool for defect detection of wire rope.
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 (c) 2016 APA, all rights reserved).
Homotopy arguments for quantized Hall conductivity
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.
CERN PhotoLab
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.
Anomalous hall effect in ferromagnetic semiconductors
Czech Academy of Sciences Publication Activity Database
Jungwirth, Tomáš; Niu, Q.; MacDonald, A. H.
2002-01-01
Roč. 88, č. 20 (2002), s. 207208-1-207208-4 ISSN 0031-9007 R&D Projects: GA ČR GA202/02/0912; GA MŠk OC P5.10 Institutional research plan: CEZ:AV0Z1010914 Keywords : ferromagnetic semiconductors * anomalous Hall effect Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 7.323, year: 2002
A hall for assembly and cryogenic tests
International Nuclear Information System (INIS)
Beaunier, J.; Buhler, S.; Caruette, A.; Chevrollier, R.; Junquera, T.; Le Scornet, J.C.
1999-01-01
Cryodrome, an assembly hall and the testing ground for cryogenic equipment and R and D experiments for the superconducting cavities is going to be transformed for its future missions. The cryogenic utilities, especially the He low pressure pumping capacity, was rearranged and extended to a new area. Space was provided to install CRYHOLAB, a new horizontal cryostat for cavity testing. Automatic control and supervision of the utilities and the experimental area are rebuilt and updated. (authors)
Generic superweak chaos induced by Hall effect
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 κ2 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.
Anode Fall Formation in a Hall Thruster
International Nuclear Information System (INIS)
Dorf, Leonid A.; Raitses, Yevgeny F.; Smirnov, Artem N.; Fisch, Nathaniel J.
2004-01-01
As was reported in our previous work, accurate, nondisturbing near-anode measurements of the plasma density, electron temperature, and plasma potential performed with biased and emissive probes allowed the first experimental identification of both electron-repelling (negative anode fall) and electron-attracting (positive anode fall) anode sheaths in Hall thrusters. An interesting new phenomenon revealed by the probe measurements is that the anode fall changes from positive to negative upon removal of the dielectric coating, which appears on the anode surface during the course of Hall thruster operation. As reported in the present work, energy dispersion spectroscopy analysis of the chemical composition of the anode dielectric coating indicates that the coating layer consists essentially of an oxide of the anode material (stainless steel). However, it is still unclear how oxygen gets into the thruster channel. Most importantly, possible mechanisms of anode fall formation in a Hall thruster with a clean and a coated anodes are analyzed in this work; practical implication of understanding the general structure of the electron-attracting anode sheath in the case of a coated anode is also discussed
Josephson tunneling in bilayer quantum Hall system
International Nuclear Information System (INIS)
Ezawa, Z.F.; Tsitsishvili, G.; Sawada, A.
2012-01-01
A Bose–Einstein condensation is formed by composite bosons in the quantum Hall state. A composite boson carries the fundamental charge (−e). We investigate Josephson tunneling of such charges in the bilayer quantum Hall system at the total filling ν=1. We show the existence of the critical current for the tunneling current to be coherent and dissipationless. Our results explain recent experiments due to [L. Tiemann, Y. Yoon, W. Dietsche, K. von Klitzing, W. Wegscheider, Phys. Rev. B 80 (2009) 165120] and due to [Y. Yoon, L. Tiemann, S. Schmult, W. Dietsche, K. von Klitzing, Phys. Rev. Lett. 104 (2010) 116802]. We predict also how the critical current changes as the sample is tilted in the magnetic field. -- Highlights: ► Composite bosons undergo Bose–Einstein condensation to form the bilayer quantum Hall state. ► A composite boson is a single electron bound to a flux quantum and carries one unit charge. ► Quantum coherence develops due to the condensation. ► Quantum coherence drives the supercurrent in each layer and the tunneling current. ► There exists the critical input current so that the tunneling current is coherent and dissipationless.
Familial Pallister-Hall in adulthood.
Talsania, Mitali; Sharma, Rohan; Sughrue, Michael E; Scofield, R Hal; Lim, Jonea
2017-10-01
Pallister Hall syndrome is autosomal dominant disorder usually diagnosed in infants and children. Current diagnostic criteria include presence of hypothalamic hamartoma, post axial polydactyly and positive family history, but the disease has variable manifestations. Herein we report Pallister Hall syndrome diagnosed in a family where both patients were adults. A 59 year old man developed seizures 4 years prior to our evaluation of him, at which time imaging showed a hypothalamic hamartoma. The seizures were controlled medically. He did well until he had visual changes after a traumatic head injury. Repeat MRI showed slight expansion of the mass with formal visual field testing demonstrating bitemporal hemianopsia. There was no evidence of pituitary dysfunction except for large urine volume. He underwent surgery to debulk the hamartoma and the visual field defects improved. There was no hypopituitarism post-operatively, and the polydyspia resolved. His 29 year old daughter also had seizures and hypothalamic hamartoma. Both patients had had polydactyly with prior surgical correction in childhood. The daughter underwent genetic testing, which revealed a previously undescribed heterozygous single base pair deletion in exon 13 of the GLI3 gene causing a frameshift mutation. Further investigation into family history revealed multiple members in previous generations with polydactyly and/or seizures. Pallister-Hall syndrome is caused by an inherited autosomal dominant or de novo mutation in GLI3 gene. This rare syndrome has not had prevalence defined, however. Generally, diagnoses are made in the pediatric population. Our report adds to the few cases detected in adulthood.
Directory of Open Access Journals (Sweden)
Taharuddin Nurul Shima
2016-01-01
Full Text Available In Negeri Sembilan, they are still practicing Minangkabau culture and custom. Element of uniqueness in Negeri. Sembilan has been shown on its architectural where the houses have dramatic curved roof structures with multitier. The art and architecture features a unique regional style. This house fills with cultural values, customs and reflects the people’s understanding about designing art and architecture that is in harmony with nature. The house serves as a residence, a hall for family meetings, and for ceremonial activities. This research, studies the understanding of art students towards the characteristic that are found in the Negeri Sembilan Minangkabau Traditional House (NSMTH in Negeri Sembilan, Malaysia. The objectives are to identify the element of characteristic that shows the identity of Negeri Sembilan Minangkabau Traditional House and to determine the level of understanding on characteristic of a Minangkabau house by art students. Scope of this research is on understanding of Faculty Art & Design student that has syllabus on Malay art. The research methodology that been use in this research is quantitative where surveys are made among the art students
Habitat Restoration/Enhancement Fort Hall Reservation : 2008 Annual Report.
Energy Technology Data Exchange (ETDEWEB)
Osborne, Hunter [Shoshone Bannock Tribes
2009-07-23
Habitat enhancement, protection and monitoring were the focus of the Resident Fisheries Program during 2008. Enhancement and protection included sloping, fencing and planting wetlands plugs at sites on Spring Creek (Head-waters). Many previously constructed instream structures (rock barbs and wing dams) were repaired throughout the Fort Hall Indian Reservation (Reservation). Physical sampling during 2008 included sediment and depth measurements (SADMS) in Spring Creek at the Car Removal site. SADMS, used to track changes in channel morphology and specifically track movements of silt through Bottoms stream systems were completed for 5 strata on Spring Creek. Water temperature and chemistry were monitored monthly on Spring Creek, Clear Creek, Diggie Creek, and Portneuf (Jimmy Drinks) and Blackfoot rivers. Fish population densities and biomass were sampled in five reservation streams which included nine sites. Sampling protocols were identical to methods used in past years. Numbers of fish in Spring Creek series remained relatively low, however, there was an increase of biomass overall since 1993. Salmonid fry densities were monitored near Broncho Bridge and were similar to 2006, and 2007, however, as in years past, high densities of macrophytes make it very difficult to see fry in addition to lack of field technicians. Mean catch rate by anglers on Bottoms streams stayed the same as 2007 at 1.5/hr. Numbers of fish larger than 18-inches caught by anglers increased from 2007 at .20 to .26/hr.
Particle-in-cell numerical simulations of a cylindrical Hall thruster with permanent magnets
Miranda, Rodrigo A.; Martins, Alexandre A.; Ferreira, José L.
2017-10-01
The cylindrical Hall thruster (CHT) is a propulsion device that offers high propellant utilization and performance at smaller dimensions and lower power levels than traditional Hall thrusters. In this paper we present first results of a numerical model of a CHT. This model solves particle and field dynamics self-consistently using a particle-in-cell approach. We describe a number of techniques applied to reduce the execution time of the numerical simulations. The specific impulse and thrust computed from our simulations are in agreement with laboratory experiments. This simplified model will allow for a detailed analysis of different thruster operational parameters and obtain an optimal configuration to be implemented at the Plasma Physics Laboratory at the University of Brasília.
Breathing oscillations in enlarged cylindrical-anode-layer Hall plasma accelerator
Energy Technology Data Exchange (ETDEWEB)
Geng, S. F.; Wang, C. X. [Southwestern Institute of Physics, Chengdu 610041 (China); Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China); Tang, D. L.; Qiu, X. M. [Southwestern Institute of Physics, Chengdu 610041 (China); Fu, R. K. Y. [Plasma Technology Limited, Festival Walk Tower, Tat Chee Avenue, Kowloon, Hong Kong (China); Chu, Paul K. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China)
2013-05-28
Breathing oscillations in the discharge of an enlarged cylindrical-anode-layer Hall plasma accelerator are investigated by three-dimensional particle-in-cell (PIC) simulation. Different from the traditional breathing mode in a circular Hall plasma accelerator, the bulk plasma oscillation here is trigged by the potential barrier generated by the concentrated ion beam and substantial enough to compete with the anode voltage. The electric field near the anode is suppressed by the potential barrier thereby decreasing the electron density by {approx}36%. The discharge is restored to the normal level after the concentrated beam explodes and then it completes one cycle of electro-driven breathing oscillation. The breathing mode identified by the PIC simulation has a frequency range of {approx}156 kHz-{approx}250 kHz and does not vary monotonically with the discharge voltage.
High-speed Internet Use and Academic Gratifications in the College Residence.
Matthews, Denise; Schrum, Lynne
2003-01-01
A multimethod exploration of undergraduates' high-speed Internet use in residence halls took a uses-and-gratifications approach and revealed Internet use as integral to students' lives. Students' negative comments about Internet distractions from academic work led to identification of an individual difference variable, internal locus of control of…
Use of a Behavioral Contract with Resident Assistants: Prelude to a Health Fair.
Morgan, John D.; Hyner, Gerald C.
1984-01-01
Presents a conceptual model which focuses on goals of student government in residence halls. The model has two fundamental processes. One focuses on short term goals and activities catering to creation of environment. The second has long term effects referred to as lifelong personal development. (JAC)
Commemorative Symposium on the Hall Effect and its Applications
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...
Experimental test of 200 W Hall thruster with titanium wall
Ding, Yongjie; Sun, Hezhi; Peng, Wuji; Xu, Yu; Wei, Liqiu; Li, Hong; Li, Peng; Su, Hongbo; Yu, Daren
2017-05-01
We designed a 200 W Hall thruster based on the technology of pushing down a magnetic field with two permanent magnetic rings. Boron nitride (BN) is an important insulating wall material for Hall thrusters. The discharge characteristics of the designed Hall thruster were studied by replacing BN with titanium (Ti). Experimental results show that the designed Hall thruster can discharge stably for a long time under a Ti channel. Experiments were performed to determine whether the channel and cathode are electrically connected. When the channel wall and cathode are insulated, the divergence angle of the plume increases, but the performance of the Hall thruster is improved in terms of thrust, specific impulse, anode efficiency, and thrust-to-power ratio. Ti exhibits a powerful antisputtering capability, a low emanation rate of gas, and a large structural strength, making it a potential candidate wall material in the design of low-power Hall thrusters.
Resident Characteristics Report
Department of Housing and Urban Development — The Resident Characteristics Report summarizes general information about households who reside in Public Housing, or who receive Section 8 assistance. The report...
Residents' Perceptions of Property Rating in a Traditional African City
African Journals Online (AJOL)
2015-04-22
Apr 22, 2015 ... Council for the Development of Social Science Research in Africa, 2014. (ISSN 0850-3907) ... The IGR includes the local tax, property tax and fees and charges. Of importance ... the world. .... Each of the above is referred to as the suburban, intermediate or ... for making and levying rates to rating authorities.
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.
The Hall module of an exact category with duality
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...
DESIGN OF SUBSOIL IMPROVEMENT BELOW HALL FLOORS
Directory of Open Access Journals (Sweden)
Peter Turček
2017-10-01
Full Text Available The construction of an industrial park is now being prepared near the town of Nitra. The investor fixed very strict conditions for the bearing capacity and, above all, the settlement of halls and their floors. The geological conditions at the construction site are difficult: there are soft clay soils with high compressibility and low bearing capacity. A detailed analysis of soil improvement was made. Stone columns were prepared to be fitted into an approximately 5 m thick layer of soft clay. The paper shows the main steps used in the design of the stone columns.
Optically induced Hall effect in semiconductors
Energy Technology Data Exchange (ETDEWEB)
Idrish Miah, M; Gray, E Mac A, E-mail: m.miah@griffith.edu.a [Nanoscale Science and Technology Centre, Griffith University, Nathan, Brisbane, QLD 4111 (Australia)
2009-03-01
We describe an experiment which investigates the effect of a longitudinal electric field on the spin-polarized carriers generated by a circularly polarized light in semiconductors. Our experiment observes the effect as a Hall voltage resulting from nonequilibrium magnetization induced by the spin-carrier electrons accumulating at the transverse boundaries of the sample as a result of asymmetries in scattering for spin-up and spin-down electrons in the presence of spin-orbit interaction. It is found that the effect depends on the longitudinal electric field and doping density as well as on temperature. The results are presented by discussing the dominant spin relaxation mechanisms in semiconductors.
Fractional quantization and the quantum hall effect
International Nuclear Information System (INIS)
Guerrero, J.; Calixto, M.; Aldaya, V.
1998-01-01
Quantization with constrains is considered in a group-theoretical framework, providing a precise characterization of the set of good operators, i.e., those preserving the constrained Hilbert space, in terms of the representation of the subgroup of constraints. This machinery is applied to the quantization of the torus as symplectic manifold, obtaining that fractional quantum numbers are permitted, provided that we allow for vector valued representations. The good operators turn out to be the Wilson loops and, for certain representations of the subgroup of constraints, the modular transformations. These results are applied to the Fractional Quantum Hall Effect, where interesting implications are derived
Excitons in the Fractional Quantum Hall Effect
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.
The fractional quantum Hall effect goes organic
International Nuclear Information System (INIS)
Smet, Jurgen
2000-01-01
Physicists have been fascinated by the behaviour of two-dimensional electron gases for the past two decades. All of these experiments were performed on inorganic semiconductor devices, most of them based on gallium arsenide. Indeed, until recently it was thought that the subtle effects that arise due to electron-electron interactions in these devices required levels of purity that could not be achieved in other material systems. However, Hendrik Schoen, Christian Kloc and Bertram Batlogg of Bell Laboratories in the US have now observed the fractional quantum Hall effect - the most dramatic signature of electron-electron interactions - in two organic semiconductors. (U.K.)
A Compton polarimeter for CEBAF Hall A
Energy Technology Data Exchange (ETDEWEB)
Bardin, G; Cavata, C; Frois, B; Juillard, M; Kerhoas, S; Languillat, J C; Legoff, J M; Mangeot, P; Martino, J; Platchkov, S; Rebourgeard, P; Vernin, P; Veyssiere, C; CEBAF Hall A Collaboration
1994-09-01
The physic program at CEBAF Hall A includes several experiments using 4 GeV polarized electron beam: parity violation in electron elastic scattering from proton and {sup 4}He, electric form factor of the proton by recoil polarization, neutron spin structure function at low Q{sup 2}. Some of these experiments will need beam polarization measurement and monitoring with an accuracy close to 4%, for beam currents ranging from 100 nA to 100 microA. A project of a Compton Polarimeter that will meet these requirements is presented. It will comprise four dipoles and a symmetric cavity consisting of two identical mirrors. 1 fig., 10 refs.
Hall conductivity for two dimensional magnetic systems
International Nuclear Information System (INIS)
Desbois, J.; Ouvry, S.; Texier, C.
1996-01-01
A Kubo inspired formalism is proposed to compute the longitudinal and transverse dynamical conductivities of an electron in a plane (or a gas of electrons at zero temperature) coupled to the potential vector of an external local magnetic field, with the additional coupling of the spin degree of freedom of the electron to the local magnetic field (Pauli Hamiltonian). As an example, the homogeneous magnetic field Hall conductivity is rederived. The case of the vortex at the origin is worked out in detail. A perturbative analysis is proposed for the conductivity in the random magnetic impurity problem (Poissonian vortices in the plane). (author)
Transit-time instability in Hall thrusters
International Nuclear Information System (INIS)
Barral, Serge; Makowski, Karol; Peradzynski, Zbigniew; Dudeck, Michel
2005-01-01
Longitudinal waves characterized by a phase velocity of the order of the velocity of ions have been recurrently observed in Hall thruster experiments and simulations. The origin of this so-called ion transit-time instability is investigated with a simple one-dimensional fluid model of a Hall thruster discharge in which cold ions are accelerated between two electrodes within a quasineutral plasma. A short-wave asymptotics applied to linearized equations shows that plasma perturbations in such a device consist of quasineutral ion acoustic waves superimposed on a background standing wave generated by discharge current oscillations. Under adequate circumstances and, in particular, at high ionization levels, acoustic waves are amplified as they propagate, inducing strong perturbation of the ion density and velocity. Responding to the subsequent perturbation of the column resistivity, the discharge current generates a standing wave, the reflection of which sustains the generation of acoustic waves at the inlet boundary. A calculation of the frequency and growth rate of this resonance mechanism for a supersonic ion flow is proposed, which illustrates the influence of the ionization degree on their onset and the approximate scaling of the frequency with the ion transit time. Consistent with experimental reports, the traveling wave can be observed on plasma density and velocity perturbations, while the plasma potential ostensibly oscillates in phase along the discharge
Cylindrical Hall Thrusters with Permanent Magnets
International Nuclear Information System (INIS)
Raitses, Yevgeny; Merino, Enrique; Fisch, Nathaniel J.
2010-01-01
The use of permanent magnets instead of electromagnet coils for low power Hall thrusters can offer a significant reduction of both the total electric power consumption and the thruster mass. Two permanent magnet versions of the miniaturized cylindrical Hall thruster (CHT) of different overall dimensions were operated in the power range of 50W-300 W. The discharge and plasma plume measurements revealed that the CHT thrusters with permanent magnets and electromagnet coils operate rather differently. In particular, the angular ion current density distribution from the permanent magnet thrusters has an unusual halo shape, with a majority of high energy ions flowing at large angles with respect to the thruster centerline. Differences in the magnetic field topology outside the thruster channel and in the vicinity of the channel exit are likely responsible for the differences in the plume characteristics measured for the CHTs with electromagnets and permanent magnets. It is shown that the presence of the reversing-direction or cusp-type magnetic field configuration inside the thruster channel without a strong axial magnetic field outside the thruster channel does not lead to the halo plasma plume from the CHT.
Bimetric Theory of Fractional Quantum Hall States
Directory of Open Access Journals (Sweden)
Andrey Gromov
2017-11-01
Full Text Available We present a bimetric low-energy effective theory of fractional quantum Hall (FQH states that describes the topological properties and a gapped collective excitation, known as the Girvin-Macdonald-Platzman (GMP mode. The theory consists of a topological Chern-Simons action, coupled to a symmetric rank-2 tensor, and an action à la bimetric gravity, describing the gapped dynamics of a spin-2 mode. The theory is formulated in curved ambient space and is spatially covariant, which allows us to restrict the form of the effective action and the values of phenomenological coefficients. Using bimetric theory, we calculate the projected static structure factor up to the k^{6} order in the momentum expansion. To provide further support for the theory, we derive the long-wave limit of the GMP algebra, the dispersion relation of the GMP mode, and the Hall viscosity of FQH states. The particle-hole (PH transformation of the theory takes a very simple form, making the duality between FQH states and their PH conjugates manifest. We also comment on the possible applications to fractional Chern insulators, where closely related structures arise. It is shown that the familiar FQH observables acquire a curious geometric interpretation within the bimetric formalism.
Hypernuclear Spectroscopy at JLab Hall C
International Nuclear Information System (INIS)
Hashimoto, Osamu; Chiba, Atsushi; Doi, Daisuke; Fujii, Yu; Toshiyuki, Gogami; Kanda, Hiroki; Kaneta, M.; Kawama, Daisuke; Maeda, Kazushige; Maruta, Tomofumi; Matsumura, Akihiko; Nagao, Sho; Nakamura, Satoshi; Shichijo, Ayako; Tamura, Hirokazu; Taniya, Naotaka; Yamamoto, Taku; Yokota, Kosuke; Kato, S.; Sato, Yoshinori; Takahashi, Toshiyuki; Noumi, Hiroyuki; Motoba, T.; Hiyama, E.; Albayrak, Ibrahim; Ates, Ozgur; Chen, Chunhua; Christy, Michael; Keppel, Cynthia; Kohl, Karl; Li, Ya; Liyanage, Anusha Habarakada; Tang, Liguang; Walton, T.; Ye, Zhihong; Yuan, Lulin; Zhu, Lingyan; Baturin, Pavlo; Boeglin, Werner; Dhamija, Seema; Markowitz, Pete; Raue, Brian; Reinhold, Joerg; Hungerford, Ed; Ent, Rolf; Fenker, Howard; Gaskell, David; Horn, Tanja; Jones, Mark; Smith, Gregory; Vulcan, William; Wood, Stephen; Johnston, C.; Simicevic, Neven; Wells, Stephen; Samanta, Chhanda; Hu, Bitao; Shen, Ji; Wang, W.; Zhang, Xiaozhuo; Zhang, Yi; Feng, Jing; Fu, Y.; Zhou, Jian; Zhou, S.; Jiang, Yi; Lu, H.; Yan, Xinhu; Ye, Yunxiu; Gan, Liping; Ahmidouch, Abdellah; Danagoulian, Samuel; Gasparian, Ashot; Elaasar, Mostafa; Wesselmann, Frank; Asaturyan, Arshak; Margaryan, Amur; Mkrtchyan, Arthur; Mkrtchyan, Hamlet; Tadevosyan, Vardan; Androic, Darko; Furic, Miroslav; Petkovic, Tomislav; Seva, Tomislav; Niculescu, Gabriel; Niculescu, Maria-Ioana; Rodriguez, Victor; Cisbani, Evaristo; Cusanno, Francesco; Garibaldi, Franco; Urciuoli, Guido; De Leo, Raffaele; Maronne, S.; Achenbach, Carsten; Pochodzalla, J.
2010-01-01
Since the 1st generation experiment, E89-009, which was successfully carried out as a pilot experiment of (e,e(prime)K + ) hypernuclear spectroscopy at JLab Hall C in 2000, precision hypernuclear spectroscopy by the (e,e(prime)K + ) reactions made considerable progress. It has evolved to the 2nd generation experiment, E01-011, in which a newly constructed high resolution kaon spectrometer (HKS) was installed and the 'Tilt method' was adopted in order to suppress large electromagnetic background and to run with high luminosity. Preliminary high-resolution spectra of 7 ΛHe and 28 ΛAl together with that of 12 ΛB that achieved resolution better than 500 keV(FWHM) were obtained. The third generation experiment, E05-115, has completed data taking with an experimental setup combining a new splitter magnet, high resolution electron spectrometer (HES) and the HKS used in the 2nd generation experiment. The data were accumulated with targets of 7 Li, 9 Be, 10 B, 12 C and 52 Cr as well as with those of CH 2 and H 2 O for calibration. The analysis is under way with particular emphasis of determining precision absolute hypernuclear masses. In this article, hypernuclear spectroscopy program in the wide mass range at JLab Hall C that has undergone three generation is described.
Bimetric Theory of Fractional Quantum Hall States
Gromov, Andrey; Son, Dam Thanh
2017-10-01
We present a bimetric low-energy effective theory of fractional quantum Hall (FQH) states that describes the topological properties and a gapped collective excitation, known as the Girvin-Macdonald-Platzman (GMP) mode. The theory consists of a topological Chern-Simons action, coupled to a symmetric rank-2 tensor, and an action à la bimetric gravity, describing the gapped dynamics of a spin-2 mode. The theory is formulated in curved ambient space and is spatially covariant, which allows us to restrict the form of the effective action and the values of phenomenological coefficients. Using bimetric theory, we calculate the projected static structure factor up to the k6 order in the momentum expansion. To provide further support for the theory, we derive the long-wave limit of the GMP algebra, the dispersion relation of the GMP mode, and the Hall viscosity of FQH states. The particle-hole (PH) transformation of the theory takes a very simple form, making the duality between FQH states and their PH conjugates manifest. We also comment on the possible applications to fractional Chern insulators, where closely related structures arise. It is shown that the familiar FQH observables acquire a curious geometric interpretation within the bimetric formalism.
Repurposing the Caltech Robinson Hall Coelostat
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
Undulator Hall Air Temperature Fault Scenarios
International Nuclear Information System (INIS)
Sevilla, J.
2010-01-01
Recent experience indicates that the LCLS undulator segments must not, at any time following tuning, be allowed to change temperature by more than about ±2.5 C or the magnetic center will irreversibly shift outside of acceptable tolerances. This vulnerability raises a concern that under fault conditions the ambient temperature in the Undulator Hall might go outside of the safe range and potentially could require removal and retuning of all the segments. In this note we estimate changes that can be expected in the Undulator Hall air temperature for three fault scenarios: (1) System-wide power failure; (2) Heating Ventilation and Air Conditioning (HVAC) system shutdown; and (3) HVAC system temperature regulation fault. We find that for either a system-wide power failure or an HVAC system shutdown (with the technical equipment left on), the short-term temperature changes of the air would be modest due to the ability of the walls and floor to act as a heat ballast. No action would be needed to protect the undulator system in the event of a system-wide power failure. Some action to adjust the heat balance, in the case of the HVAC power failure with the equipment left on, might be desirable but is not required. On the other hand, a temperature regulation failure of the HVAC system can quickly cause large excursions in air temperature and prompt action would be required to avoid damage to the undulator system.
Maddry, Joseph K; Varney, Shawn M; Sessions, Daniel; Heard, Kennon; Thaxton, Robert E; Ganem, Victoria J; Zarzabal, Lee A; Bebarta, Vikhyat S
2014-12-01
Simulation-based teaching (SIM) is a common method for medical education. SIM exposes residents to uncommon scenarios that require critical, timely actions. SIM may be a valuable training method for critically ill poisoned patients whose diagnosis and treatment depend on key clinical findings. Our objective was to compare medical simulation (SIM) to traditional lecture-based instruction (LEC) for training emergency medicine (EM) residents in the acute management of critically ill poisoned patients. EM residents completed two pre-intervention questionnaires: (1) a 24-item multiple-choice test of four toxicological emergencies and (2) a questionnaire using a five-point Likert scale to rate the residents' comfort level in diagnosing and treating patients with specific toxicological emergencies. After completing the pre-intervention questionnaires, residents were randomized to SIM or LEC instruction. Two toxicologists and three EM physicians presented four toxicology topics to both groups in four 20-min sessions. One group was in the simulation center, and the other in a lecture hall. Each group then repeated the multiple-choice test and questionnaire immediately after instruction and again at 3 months after training. Answers were not discussed. The primary outcome was comparison of immediate mean post-intervention test scores and final scores 3 months later between SIM and LEC groups. Test score outcomes between groups were compared at each time point (pre-test, post-instruction, 3-month follow-up) using Wilcoxon rank sum test. Data were summarized by descriptive statistics. Continuous variables were characterized by means (SD) and tested using t tests or Wilcoxon rank sum. Categorical variables were summarized by frequencies (%) and compared between training groups with chi-square or Fisher's exact test. Thirty-two EM residents completed pre- and post-intervention tests and comfort questionnaires on the study day. Both groups had higher post-intervention mean test
Discharge Oscillations in a Permanent Magnet Cylindrical Hall-Effect Thruster
Polzin, K. A.; Sooby, E. S.; Raitses, Y.; Merino, E.; Fisch, N. J.
2009-01-01
Measurements of the discharge current in a cylindrical Hall thruster are presented to quantify plasma oscillations and instabilities without introducing an intrusive probe into the plasma. The time-varying component of the discharge current is measured using a current monitor that possesses a wide frequency bandwidth and the signal is Fourier transformed to yield the frequency spectra present, allowing for the identification of plasma oscillations. The data show that the discharge current oscillations become generally greater in amplitude and complexity as the voltage is increased, and are reduced in severity with increasing flow rate. The breathing mode ionization instability is identified, with frequency as a function of discharge voltage not increasing with discharge voltage as has been observed in some traditional Hall thruster geometries, but instead following a scaling similar to a large-amplitude, nonlinear oscillation mode recently predicted in for annular Hall thrusters. A transition from lower amplitude oscillations to large relative fluctuations in the oscillating discharge current is observed at low flow rates and is suppressed as the mass flow rate is increased. A second set of peaks in the frequency spectra are observed at the highest propellant flow rate tested. Possible mechanisms that might give rise to these peaks include ionization instabilities and interactions between various oscillatory modes.
Mary E. Hall: Dawn of the Professional School Librarian
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…
What is the Hallé? | Smith | Philosophical Papers
African Journals Online (AJOL)
The bulk of the paper examines the difficulty of reconciling the view that the Hallé is several individuals with two prima facie plausible theses about the manner of its persistence through time. The paper is structured around some remarks made by Peter Simons about groups, and the Hallé in particular, in his Parts.
Spin hall effect associated with SU(2) gauge field
Tao, Y.
2010-01-01
In this paper, we focus on the connection between spin Hall effect and spin force. Here we investigate that the spin force due to spin-orbit coupling, which, in two-dimensional system, is equivalent to forces of Hirsch and Chudnovsky besides constant factors 3 and frac{3}{2} respectively, is a part of classic Anandan force, and that the spin Hall effect is an anomalous Hall effect. Furthermore, we develop the method of AC phase to derive the expression for the spin force, and note that the most basic spin Hall effect indeed originate from the AC phase and is therefore an intrinsic quantum mechanical property of spin. This method differs from approach of Berry phase in the study of anomalous Hall effect , which is the intrinsic property of the perfect crystal. On the other hand, we use an elegant skill to show that the Chudnovsky-Drude model is reasonable. Here we have improved the theoretical values of spin Hall conductivity of Chudnovsky. Compared to the theoretical values of spin Hall conductivity in the Chudnovsky-Drude model, ours are in better agreement with experimentation. Finally, we discuss the relation between spin Hall effect and fractional statistics.
Energy spectrum, dissipation, and spatial structures in reduced Hall magnetohydrodynamic
Energy Technology Data Exchange (ETDEWEB)
Martin, L. N.; Dmitruk, P. [Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and IFIBA, CONICET, Ciudad Universitaria, 1428 Buenos Aires (Argentina); Gomez, D. O. [Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and IFIBA, CONICET, Ciudad Universitaria, 1428 Buenos Aires (Argentina); Instituto de Astronomia y Fisica del Espacio, CONICET, Buenos Aires (Argentina)
2012-05-15
We analyze the effect of the Hall term in the magnetohydrodynamic turbulence under a strong externally supported magnetic field, seeing how this changes the energy cascade, the characteristic scales of the flow, and the dynamics of global magnitudes, with particular interest in the dissipation. Numerical simulations of freely evolving three-dimensional reduced magnetohydrodynamics are performed, for different values of the Hall parameter (the ratio of the ion skin depth to the macroscopic scale of the turbulence) controlling the impact of the Hall term. The Hall effect modifies the transfer of energy across scales, slowing down the transfer of energy from the large scales up to the Hall scale (ion skin depth) and carrying faster the energy from the Hall scale to smaller scales. The final outcome is an effective shift of the dissipation scale to larger scales but also a development of smaller scales. Current sheets (fundamental structures for energy dissipation) are affected in two ways by increasing the Hall effect, with a widening but at the same time generating an internal structure within them. In the case where the Hall term is sufficiently intense, the current sheet is fully delocalized. The effect appears to reduce impulsive effects in the flow, making it less intermittent.
Quantifying Spin Hall Angles from Spin Pumping : Experiments and Theory
Mosendz, O.; Pearson, J.E.; Fradin, F.Y.; Bauer, G.E.W.; Bader, S.D.; Hoffmann, A.
2010-01-01
Spin Hall effects intermix spin and charge currents even in nonmagnetic materials and, therefore, ultimately may allow the use of spin transport without the need for ferromagnets. We show how spin Hall effects can be quantified by integrating Ni80Fe20|normal metal (N) bilayers into a coplanar
Stuart Hall on Racism and the Importance of Diasporic Thinking
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…
Theory of the quantum hall effects in lattice systems
International Nuclear Information System (INIS)
Kliros, G.S.
1990-06-01
The Fractional Quantum Hall Effect is identified as an Integral Quantum Hall Effect of electrons on a lattice with an even number of statistical flux quanta. A variational wavefunction in terms of the Hofstadter lattice eigenstates is proposed. (author). 21 refs
Bulk Versus Edge in the Quantum Hall Effect
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.
Critical current in the Integral Quantum Hall Effect
International Nuclear Information System (INIS)
Kostadinov, I.Z.
1985-11-01
A multiparticle theory of the Integral Quantum Hall Effect (IQHE) was constructed operating with pairs wave function as an order parameter. The IQHE is described with bosonic macroscopic states while the fractional QHE with fermionic ones. The calculation of the critical current and Hall conductivity temperature dependence is presented. (author)
Useful Pedagogical Applications of the Classical Hall Effect
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…
Medical humanities: a resident doctor's perspective.
Pauranik, Anvita
2012-01-01
The barrage of competitive examinations, overwork, sleep deprivation, and the pressure of expectations all combine to destroy the dreams that resident doctors have when they start medical school. The empathy they had before entering this field fades away, and they eventually become insensitive to their patients. Medical humanities may be the means to halt this trend. Sensitising young minds, using the arts, literature, history and lessons on social issues, may bring about a paradigm shift in these doctors' outlook towards their patients. However, for the humanities to be integrated into medical education, the current curriculum must be modified and made more clinically and socially relevant. Further, the humanities cannot be taught in lecture halls; they need to be integrated into all aspects of medical school. For this, the medical school faculty should be sensitised to, and trained in, humanities education.
A Novel Hall Effect Sensor Using Elaborate Offset Cancellation Method
Directory of Open Access Journals (Sweden)
Vlassis N. Petoussis
2009-01-01
Full Text Available The Hall effect is caused by a traverse force that is formed in the electrons or holes of metal element or semiconductor when are polarized by current source and simultaneously all the system it is found vertical in external magnetic field. Result is finally the production of difference of potential (Hall voltage in address vertical in that of current and magnetic field directions. In the present work is presented a new Hall sensor exploiting the former operation. In combination with his pioneering form and using dynamic spinning current technique with an elaborate sequence, it leads to satisfactory results of produced Hall voltage with small noise in a presence of external magnetic field. Anyone can see both the spinning current and anti-Hall technique in the same sensor simultaneously.
Migrants and Their Experiences of Time: Edward T. Hall Revisited
Directory of Open Access Journals (Sweden)
Elisabeth Schilling
2009-01-01
Full Text Available In this paper we reassess the scientific heritage of Edward T. HALL and his contribution to the area of intercultural communication. The key objectives of our study are to demonstrate the applicability of HALL's theory of culture to empirical research and to establish its compatibility with other methods. Specifically, we propose that Alfred SCHÜTZ's phenomenology of sociality be taken as an extension to HALL. The connection between HALL and SCHÜTZ is made possible by the mutual emphases on the temporal dimension of culture and the temporal aspects of migration. With these foci we analyze six narratives by two groups of migrants: German and Russian. By combining HALL's theory of the cultural time with SCHÜTZ's phenomenological perspective on time and the Other and then applying them to empirical data, we show the terms in which different cultures experience time. URN: urn:nbn:de:0114-fqs0901357
Unconventional quantum Hall effect in Floquet topological insulators
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.
Magnetic Measurements of the Background Field in the Undulator Hall
International Nuclear Information System (INIS)
Fisher, Andrew
2010-01-01
The steel present in the construction of the undulator hall facility has the potential for changing the ambient fields present in the undulator hall. This note describes a measurement done to make a comparison between the fields in the hall and in the Magnetic Measurement Facility. In order for the undulators to have the proper tuning, the background magnetic field in the Undulator Hall should agree with the background field in the Magnetic Measurements Facility within .5 gauss. In order to verify that this was the case measurements were taken along the length of the undulator hall, and the point measurements were compared to the mean field which was measured on the MMF test bench.
Unconventional quantum Hall effect in Floquet topological insulators
Tahir, M.; Vasilopoulos, P.; Schwingenschlö gl, Udo
2016-01-01
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.
Brandt, M.J.; Reyna, C.
2014-01-01
Fundamentalism is consistently related to racial prejudice (Hall, Matz, & Wood, 2010), yet the mechanisms for this relationship are unclear. We identify two core values of fundamentalism, authoritarianism and traditionalism, that independently contribute to the fundamentalism‐racial prejudice
Emergency Medicine Resident Perceptions of Medical Professionalism.
Jauregui, Joshua; Gatewood, Medley O; Ilgen, Jonathan S; Schaninger, Caitlin; Strote, Jared
2016-05-01
Medical professionalism is a core competency for emergency medicine (EM) trainees; but defining professionalism remains challenging, leading to difficulties creating objectives and performing assessment. Because professionalism is dynamic, culture-specific, and often taught by modeling, an exploration of trainees' perceptions can highlight their educational baseline and elucidate the importance they place on general conventional professionalism domains. To this end, our objective was to assess the relative value EM residents place on traditional components of professionalism. We performed a cross-sectional, multi-institutional survey of incoming and graduating EM residents at four programs. The survey was developed using the American Board of Internal Medicine's "Project Professionalism" and the Accreditation Council of Graduate Medical Education definition of professionalism competency. We identified 27 attributes within seven domains: clinical excellence, humanism, accountability, altruism, duty and service, honor and integrity, and respect for others. Residents were asked to rate each attribute on a 10-point scale. We analyzed data to assess variance across attributes as well as differences between residents at different training levels or different institutions. Of the 114 residents eligible, 100 (88%) completed the survey. The relative value assigned to different professional attributes varied considerably, with those in the altruism domain valued significantly lower and those in the "respect for others" and "honor and integrity" valued significantly higher (p<0.001). Significant differences were found between interns and seniors for five attributes primarily in the "duty and service" domain (p<0.05). Among different residencies, significant differences were found with attributes within the "altruism" and "duty and service" domains (p<0.05). Residents perceive differences in the relative importance of traditionally defined professional attributes and this may
[Burnout in nursing residents].
Franco, Gianfábio Pimentel; de Barros, Alba Lúcia Bottura Leite; Nogueira-Martins, Luiz Antônio; Zeitoun, Sandra Salloum
2011-03-01
Nursing residents may experience physical and emotional exhaustion from the daily life of attending the Program. The aim of this study was to determine the Burnout incidence among Nursing Residents. An investigative, descriptive, analytical, longitudinal-prospective study was conducted with 16 Residents over two years. The Maslach Burnout Inventory was used, translated and validated for Brazil, as well as a sociodemographic/occupational data tool. Of all residents, 17.2% showed high rates in Emotional Exhaustion and Depersonalization; 18.8% showed impaired commitment in Personal Accomplishment, 75% of which belonged to specialty areas, such as Emergency Nursing, Adult and Pediatric Intensive Care. Age and specialty area were positively correlated with Personal Accomplishment. One of the Residents was identified with changes in three subscales of the Maslach Burnout Inventory, thus characterized as a Burnout Syndrome patient. Nursing Residents have profiles of disease. Knowing these factors can minimize health risks of these workers.
Impact of Smoke-Free Residence Hall Policies: The Views of Administrators at 3 State Universities
Gerson, Megan
2005-01-01
Nationwide efforts to protect the public against the health effects of secondhand smoke have prompted college and university administrators to adopt more restrictive smoking policies. Some campus officials are concerned that new policies will lead to student backlash, increased staff workloads, and an increased economic burden. To understand the…
Planar Hall Effect Sensors for Biodetection
DEFF Research Database (Denmark)
Rizzi, Giovanni
. In the second geometry (dPHEB) half of the sensor is used as a local negative reference to subtract the background signal from magnetic beads in suspension. In all applications below, the magnetic beads are magnetised using the magnetic field due to the bias current passed through the sensor, i.e., no external...... as labels and planar Hall effect bridge (PHEB) magnetic field sensor as readout for the beads. The choice of magnetic beads as label is motivated by the lack of virtually any magnetic background from biological samples. Moreover, magnetic beads can be manipulated via an external magnetic field...... hybridisation in real-time, in a background of suspended magnetic beads. This characteristic is employed in single nucleotide polymorphism (SNP) genotyping, where the denaturation of DNA is monitored in real-time upon washing with a stringency buffer. The sensor setup includes temperature control and a fluidic...
Numerical investigation of a Hall thruster plasma
International Nuclear Information System (INIS)
Roy, Subrata; Pandey, B.P.
2002-01-01
The dynamics of the Hall thruster is investigated numerically in the framework of a one-dimensional, multifluid macroscopic description of a partially ionized xenon plasma using finite element formulation. The model includes neutral dynamics, inelastic processes, and plasma-wall interaction. Owing to disparate temporal scales, ions and neutrals have been described by set of time-dependent equations, while electrons are considered in steady state. Based on the experimental observations, a third order polynomial in electron temperature is used to calculate ionization rate. The results show that in the acceleration channel the increase in the ion number density is related to the decrease in the neutral number density. The electron and ion velocity profiles are consistent with the imposed electric field. The electron temperature remains uniform for nearly two-thirds of the channel; then sharply increases to a peak before dropping slightly at the exit. This is consistent with the predicted electron gyration velocity distribution
Quantum Hall effect on Riemann surfaces
Tejero Prieto, Carlos
2009-06-01
We study the family of Landau Hamiltonians compatible with a magnetic field on a Riemann surface S by means of Fourier-Mukai and Nahm transforms. Starting from the geometric formulation of adiabatic charge transport on Riemann surfaces, we prove that Hall conductivity is proportional to the intersection product on the first homology group of S and therefore it is quantized. Finally, by using the theory of determinant bundles developed by Bismut, Gillet and Soul, we compute the adiabatic curvature of the spectral bundles defined by the holomorphic Landau levels. We prove that it is given by the polarization of the jacobian variety of the Riemann surface, plus a term depending on the relative analytic torsion.
Quantum Hall effect on Riemann surfaces
International Nuclear Information System (INIS)
Tejero Prieto, Carlos
2009-01-01
We study the family of Landau Hamiltonians compatible with a magnetic field on a Riemann surface S by means of Fourier-Mukai and Nahm transforms. Starting from the geometric formulation of adiabatic charge transport on Riemann surfaces, we prove that Hall conductivity is proportional to the intersection product on the first homology group of S and therefore it is quantized. Finally, by using the theory of determinant bundles developed by Bismut, Gillet and Soul, we compute the adiabatic curvature of the spectral bundles defined by the holomorphic Landau levels. We prove that it is given by the polarization of the jacobian variety of the Riemann surface, plus a term depending on the relative analytic torsion.
Frequency spectrum of Calder Hall reactor noise
International Nuclear Information System (INIS)
Cummins, J.D.
1960-01-01
The frequency spectrum of the noise power of Calder Hall reactor No. 1 has been obtained by analysing a tape recording of the backed off power. The root mean square noise power due to all frequencies above 0.001 cycles per second was found to be 0.13%. The noise power for this reactor, is due mainly to modulations of the power level by reactivity variations caused in turn by gas temperature changes. These gas temperature changes are caused by a Cyclic variation in the feedwater regulator to the heat exchanger. The apparatus and method used to determine the noise power are described in this memorandum. It is shown that for frequencies in the range 0.001 to 0.030 cycles per second the noise spectrum falls at 60 decibels per decade of frequency. (author)
OPTICS. Quantum spin Hall effect of light.
Bliokh, Konstantin Y; Smirnova, Daria; Nori, Franco
2015-06-26
Maxwell's equations, formulated 150 years ago, ultimately describe properties of light, from classical electromagnetism to quantum and relativistic aspects. The latter ones result in remarkable geometric and topological phenomena related to the spin-1 massless nature of photons. By analyzing fundamental spin properties of Maxwell waves, we show that free-space light exhibits an intrinsic quantum spin Hall effect—surface modes with strong spin-momentum locking. These modes are evanescent waves that form, for example, surface plasmon-polaritons at vacuum-metal interfaces. Our findings illuminate the unusual transverse spin in evanescent waves and explain recent experiments that have demonstrated the transverse spin-direction locking in the excitation of surface optical modes. This deepens our understanding of Maxwell's theory, reveals analogies with topological insulators for electrons, and offers applications for robust spin-directional optical interfaces. Copyright © 2015, American Association for the Advancement of Science.
Determination of the Hall Thruster Operating Regimes
International Nuclear Information System (INIS)
L. Dorf; V. Semenov; Y. Raitses; N.J. Fisch
2002-04-01
A quasi one-dimensional (1-D) steady-state model of the Hall thruster is presented. For the same discharge voltage two operating regimes are possible -- with and without the anode sheath. For given mass flow rate, magnetic field profile and discharge voltage a unique solution can be constructed, assuming that the thruster operates in one of the regimes. However, we show that for a given temperature profile the applied discharge voltage uniquely determines the operating regime: for discharge voltages greater than a certain value, the sheath disappears. That result is obtained over a wide range of incoming neutral velocities, channel lengths and widths, and cathode plane locations. It is also shown that a good correlation between the quasi 1-D model and experimental results can be achieved by selecting an appropriate electron mobility and temperature profile
Chaotic waves in Hall thruster plasma
International Nuclear Information System (INIS)
Peradzynski, Zbigniew; Barral, S.; Kurzyna, J.; Makowski, K.; Dudeck, M.
2006-01-01
The set of hyperbolic equations of the fluid model describing the acceleration of plasma in a Hall thruster is analyzed. The characteristic feature of the flow is the existence of a trapped characteristic; i.e. there exists a characteristic line, which never intersects the boundary of the flow region in the thruster. To study the propagation of short wave perturbations, the approach of geometrical optics (like WKB) can be applied. This can be done in a linear as well as in a nonlinear version. The nonlinear version describes the waves of small but finite amplitude. As a result of such an approach one obtains so called transport equation, which are governing the wave amplitude. Due to the existence of trapped characteristics this transport equation appears to have chaotic (turbulent) solutions in both, linear and nonlinear versions
Spin Hall magnetoresistance at high temperatures
International Nuclear Information System (INIS)
Uchida, Ken-ichi; Qiu, Zhiyong; Kikkawa, Takashi; Iguchi, Ryo; Saitoh, Eiji
2015-01-01
The temperature dependence of spin Hall magnetoresistance (SMR) in Pt/Y 3 Fe 5 O 12 (YIG) bilayer films has been investigated in a high temperature range from room temperature to near the Curie temperature of YIG. The experimental results show that the magnitude of the magnetoresistance ratio induced by the SMR monotonically decreases with increasing the temperature and almost disappears near the Curie temperature. We found that, near the Curie temperature, the temperature dependence of the SMR in the Pt/YIG film is steeper than that of a magnetization curve of the YIG; the critical exponent of the magnetoresistance ratio is estimated to be 0.9. This critical behavior of the SMR is attributed mainly to the temperature dependence of the spin-mixing conductance at the Pt/YIG interface
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....
Geometrical Description of fractional quantum Hall quasiparticles
Park, Yeje; Yang, Bo; Haldane, F. D. M.
2012-02-01
We examine a description of fractional quantum Hall quasiparticles and quasiholes suggested by a recent geometrical approach (F. D. M. Haldane, Phys. Rev. Lett. 108, 116801 (2011)) to FQH systems, where the local excess electric charge density in the incompressible state is given by a topologically-quantized ``guiding-center spin'' times the Gaussian curvature of a ``guiding-center metric tensor'' that characterizes the local shape of the correlation hole around electrons in the fluid. We use a phenomenological energy function with two ingredients: the shear distortion energy of area-preserving distortions of the fluid, and a local (short-range) approximation to the Coulomb energy of the fluctuation of charge density associated with the Gaussian curvature. Quasiparticles and quasiholes of the 1/3 Laughlin state are modeled as ``punctures'' in the incompressible fluid which then relax by geometric distortion which generates Gaussian curvature, giving rise to the charge-density profile around the topological excitation.
Cathode Effects in Cylindrical Hall Thrusters
Energy Technology Data Exchange (ETDEWEB)
Granstedt, E.M.; Raitses, Y.; Fisch, N. J.
2008-09-12
Stable operation of a cylindrical Hall thruster (CHT) has been achieved using a hot wire cathode, which functions as a controllable electron emission source. It is shown that as the electron emission from the cathode increases with wire heating, the discharge current increases, the plasma plume angle reduces, and the ion energy distribution function shifts toward higher energies. The observed effect of cathode electron emission on thruster parameters extends and clarifies performance improvements previously obtained for the overrun discharge current regime of the same type of thruster, but using a hollow cathode-neutralizer. Once thruster discharge current saturates with wire heating, further filament heating does not affect other discharge parameters. The saturated values of thruster discharge parameters can be further enhanced by optimal placement of the cathode wire with respect to the magnetic field.
On-Chip Microwave Quantum Hall Circulator
Directory of Open Access Journals (Sweden)
A. C. Mahoney
2017-01-01
Full Text Available 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 1/1000th 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 μm 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.
Mesoscopic spin Hall effect in semiconductor nanostructures
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
50 KW Class Krypton Hall Thruster Performance
Jacobson, David T.; Manzella, David H.
2003-01-01
The performance of a 50-kilowatt-class Hall thruster designed for operation on xenon propellant was measured using kryton propellant. The thruster was operated at discharge power levels ranging from 6.4 to 72.5 kilowatts. The device produced thrust ranging from 0.3 to 2.5 newtons. The thruster was operated at discharge voltages between 250 and 1000 volts. At the highest anode mass flow rate and discharge voltage and assuming a 100 percent singly charged condition, the discharge specific impulse approached the theoretical value. Discharge specific impulse of 4500 seconds was demonstrated at a discharge voltage of 1000 volts. The peak discharge efficiency was 64 percent at 650 volts.
Magnon Hall effect on the Lieb lattice.
Cao, Xiaodong; Chen, Kai; He, Dahai
2015-04-29
Ferromagnetic insulators without inversion symmetry may show magnon Hall effect (MHE) in the presence of a temperature gradient due to the existence of Dzyaloshinskii-Moriya interaction (DMI). In this theoretical study, we investigate MHE on a lattice with inversion symmetry, namely the Lieb lattice, where the DMI is introduced by adding an external electric field. We show the nontrivial topology of this model by examining the existence of edge states and computing the topological phase diagram characterized by the Chern numbers of different bands. Together with the topological phase diagram, we can further determine the sign and magnitude of the transverse thermal conductivity. The impact of the flat band possessed by this model on the thermal conductivity is discussed by computing the Berry curvature analytically.
Photonic spin Hall effect at metasurfaces.
Yin, Xiaobo; Ye, Ziliang; Rho, Junsuk; Wang, Yuan; Zhang, Xiang
2013-03-22
The spin Hall effect (SHE) of light is very weak because of the extremely small photon momentum and spin-orbit interaction. Here, we report a strong photonic SHE resulting in a measured large splitting of polarized light at metasurfaces. The rapidly varying phase discontinuities along a metasurface, breaking the axial symmetry of the system, enable the direct observation of large transverse motion of circularly polarized light, even at normal incidence. The strong spin-orbit interaction deviates the polarized light from the trajectory prescribed by the ordinary Fermat principle. Such a strong and broadband photonic SHE may provide a route for exploiting the spin and orbit angular momentum of light for information processing and communication.
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.
Nonadiabatic effects in the Quantum Hall regime
International Nuclear Information System (INIS)
Page, D.A.; Brown, E.
1993-01-01
The authors consider the effect of a finite electric field on the states of a Bloch electron in two dimensions, with a uniform magnetic field present. They make use of the concept of electric time translation symmetry and treat the electric and magnetic fields symmetrically in a time dependent formalism. In addition to a wave vector k, the states are characterized by a frequency specifying the behavior under electric time translations. An effective Hamiltonian is employed to obtain the splitting of an isolated Bloch band into open-quotes frequencyclose quotes subbands. The time-averaged velocity and energy of the states are expressed in terms of the frequency dispersion. The relationship to the Stark ladder eigenstates in a scalar potential representation of the electric field is examined. This is seen to justify the use of the averaged energy in determining occupation of the states. In the weak electric field (adiabatic) limit, an expression is recovered for the quantized Hall conductivity of a magnetic subband as a topological invariant. A numerical procedure is outlined and results obtained over a range of electric field strengths. A transition between strong and weak field regimes is seen, with level repulsions between the frequencies playing an important role. The numerical results show how the magnetic subband structure and quantized Hall conductivity emerge as the electric field becomes weaker. In this regime, the behavior can be understood by comparison to the predictions of the adiabatic approximation. The latter predicts crossings in the frequencies at certain locations in wave vector space. Nonadiabatic effects are seen to produce gaps in the frequency spectrum at these locations. 35 refs., 14 figs
Temperature dependence of collapse of quantized hall resistance
International Nuclear Information System (INIS)
Tanaka, Hiroyasu; Kawashima, Hironori; Iizuka, Hisamitsu; Fukuda, Hideaki; Kawaji, Shinji
2006-01-01
Similarity is observed in the deviation of Hall resistance from the quantized value with the increase in the source-drain current I SD in our butterfly-type Hall bars and in the Hall bars used by Jeanneret et al., while changes in the diagonal resistivity ρ xx with I SD are significantly different between these Hall bars. The temperature dependence of the critical Hall electric field F cr (T) for the collapse of R H (4) measured in these Hall bars is approximated using F cr (T) = F cr (0)(1 - (T/T cr ) 2 ). Here, the critical Hall electric field at zero temperature depends on the magnetic field B as F cr (0) ∝ B 3/2 . Theoretical considerations are given on F cr (T) on the basis of a temperature-dependent mobility edge model and a schema of temperature-dependent inter-Landau level tunneling probability arising from the Fermi distribution function. The former does not fit in with the I SD dependence of activation energy in ρ xx . (author)
Spontaneous Hall effect in a chiral p-wave superconductor
Furusaki, Akira; Matsumoto, Masashige; Sigrist, Manfred
2001-08-01
In a chiral superconductor with broken time-reversal symmetry a ``spontaneous Hall effect'' may be observed. We analyze this phenomenon by taking into account the surface properties of a chiral superconductor. We identify two main contributions to the spontaneous Hall effect. One contribution originates from the Bernoulli (or Lorentz) force due to spontaneous currents running along the surfaces of the superconductor. The other contribution has a topological origin and is related to the intrinsic angular momentum of Cooper pairs. The latter can be described in terms of a Chern-Simons-like term in the low-energy field theory of the superconductor and has some similarities with the quantum Hall effect. The spontaneous Hall effect in a chiral superconductor is, however, nonuniversal. Our analysis is based on three approaches to the problem: a self-consistent solution of the Bogoliubov-de Gennes equation, a generalized Ginzburg-Landau theory, and a hydrodynamic formulation. All three methods consistently lead to the same conclusion that the spontaneous Hall resistance of a two-dimensional superconducting Hall bar is of order h/(ekFλ)2, where kF is the Fermi wave vector and λ is the London penetration depth; the Hall resistance is substantially suppressed from a quantum unit of resistance. Experimental issues in measuring this effect are briefly discussed.
Hall current effects in dynamic magnetic reconnection solutions
International Nuclear Information System (INIS)
Craig, I.J.D.; Heerikhuisen, J.; Watson, P.G.
2003-01-01
The impact of Hall current contributions on flow driven planar magnetic merging solutions is discussed. The Hall current is important if the dimensionless Hall parameter (or normalized ion skin depth) satisfies c H >η, where η is the inverse Lundquist number for the plasma. A dynamic analysis of the problem shows, however, that the Hall current initially manifests itself, not by modifying the planar reconnection field, but by inducing a non-reconnecting perpendicular 'separator' component in the magnetic field. Only if the stronger condition c H 2 >η is satisfied can Hall currents be expected to affect the planar merging. These analytic predictions are then tested by performing a series of numerical experiments in periodic geometry, using the full system of planar magnetohydrodynamic (MHD) equations. The numerical results confirm that the nature of the merging changes dramatically when the Hall coupling satisfies c H 2 >η. In line with the analytic treatment of sheared reconnection, the coupling provided by the Hall term leads to the emergence of multiple current layers that can enhance the global Ohmic dissipation at the expense of the reconnection rate. However, the details of the dissipation depend critically on the symmetries of the simulation, and when the merging is 'head-on' (i.e., comprises fourfold symmetry) the reconnection rate can be enhanced
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....... the unconventional quantum Hall effect and then present in detail the route, which led to the most precise quantum Hall resistance universality test ever performed.......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...
Signal conditioning and processing for metallic Hall sensors.
Czech Academy of Sciences Publication Activity Database
Entler, Slavomír; Ďuran, Ivan; Sládek, P.; Vayakis, G.; Kočan, M.
2017-01-01
Roč. 123, November (2017), s. 783-786 ISSN 0920-3796. [SOFT 2016: Symposium on Fusion Technology /29./. Prague, 05.09.2016-09.09.2016] R&D Projects: GA MŠk LG14002 Institutional support: RVO:61389021 Keywords : Hall sensor * Lock-in * Synchronous detection * Current spinning * Hall effect * Planar hall effect suppression Subject RIV: JF - Nuclear Energetics OBOR OECD: Nuclear related engineering Impact factor: 1.319, year: 2016 http://www.sciencedirect.com/science/article/pii/S0920379617305070
Anomalous Hall effect in Fe/Gd bilayers
Xu, W. J.; Zhang, Bei; Liu, Z. X.; Wang, Z.; Li, W.; Wu, Z. B.; Yu, R. H.; Zhang, Xixiang
2010-01-01
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
Hall conductance and topological invariant for open systems.
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.
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...... is motivated by the fact that most concert tickets sold in Denmark relate to concerts within these genres in this kind of venue. The subjective evaluations were carried out by professional musicians and sound engineers who responded on the basis of their experiences working in these (and other) halls. From...
Anomalous Hall effect in Fe/Gd bilayers
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
All Optical Measurement Proposed for the Photovoltaic Hall Effect
International Nuclear Information System (INIS)
Oka, Takashi; Aoki, Hideo
2011-01-01
We propose an all optical way to measure the recently proposed p hotovoltaic Hall effect , i.e., a Hall effect induced by a circularly polarized light in the absence of static magnetic fields. This is done in a pump-probe experiment with the Faraday rotation angle being the probe. The Floquet extended Kubo formula for photo-induced optical response is formulated and the ac-Hall conductivity is calculated. We also point out the possibility of observing the effect in two layered graphene, three-dimensional graphite, and more generally in multi-band systems such as materials described by the dp-model.
Determination of intrinsic spin Hall angle in Pt
Energy Technology Data Exchange (ETDEWEB)
Wang, Yi; Deorani, Praveen; Qiu, Xuepeng; Kwon, Jae Hyun; Yang, Hyunsoo, E-mail: eleyang@nus.edu.sg [Department of Electrical and Computer Engineering, National University of Singapore, 117576 (Singapore)
2014-10-13
The spin Hall angle in Pt is evaluated in Pt/NiFe bilayers by spin torque ferromagnetic resonance measurements and is found to increase with increasing the NiFe thickness. To extract the intrinsic spin Hall angle in Pt by estimating the total spin current injected into NiFe from Pt, the NiFe thickness dependent measurements are performed and the spin diffusion in the NiFe layer is taken into account. The intrinsic spin Hall angle of Pt is determined to be 0.068 at room temperature and is found to be almost constant in the temperature range of 13–300 K.
Determination of intrinsic spin Hall angle in Pt
International Nuclear Information System (INIS)
Wang, Yi; Deorani, Praveen; Qiu, Xuepeng; Kwon, Jae Hyun; Yang, Hyunsoo
2014-01-01
The spin Hall angle in Pt is evaluated in Pt/NiFe bilayers by spin torque ferromagnetic resonance measurements and is found to increase with increasing the NiFe thickness. To extract the intrinsic spin Hall angle in Pt by estimating the total spin current injected into NiFe from Pt, the NiFe thickness dependent measurements are performed and the spin diffusion in the NiFe layer is taken into account. The intrinsic spin Hall angle of Pt is determined to be 0.068 at room temperature and is found to be almost constant in the temperature range of 13–300 K.
Properties of Nonabelian Quantum Hall States
Simon, Steven H.
2004-03-01
The quantum statistics of particles refers to the behavior of a multiparticle wavefunction under adiabatic interchange of two identical particles. While a three dimensional world affords the possibilities of Bosons or Fermions, the two dimensional world has more exotic possibilities such as Fractional and Nonabelian statistics (J. Frölich, in ``Nonperturbative Quantum Field Theory", ed, G. t'Hooft. 1988). The latter is perhaps the most interesting where the wavefunction obeys a ``nonabelian'' representation of the braid group - meaning that braiding A around B then B around C is not the same as braiding B around C then A around B. This property enables one to think about using these exotic systems for robust topological quantum computation (M. Freedman, A. Kitaev, et al, Bull Am Math Soc 40, 31 (2003)). Surprisingly, it is thought that quasiparticles excitations with such nonabelian statistics may actually exist in certain quantum Hall states that have already been observed. The most likely such candidate is the quantum Hall ν=5/2 state(R. L. Willett et al, Phys. Rev. Lett. 59, 1776-1779 (1987)), thought to be a so-called Moore-Read Pfaffian state(G. Moore and N. Read, Nucl Phys. B360 362 (1991)), which can be thought of as a p-wave paired superconducting state of composite fermions(M. Greiter, X. G. Wen, and F. Wilczek, PRL 66, 3205 (1991)). Using this superconducting analogy, we use a Chern-Simons field theory approach to make a number of predictions as to what experimental signatures one should expect for this state if it really is this Moore-Read state(K. Foster, N. Bonesteel, and S. H. Simon, PRL 91 046804 (2003)). We will then discuss how the nonabelian statistics can be explored in detail using a quantum monte-carlo approach (Y. Tserkovnyak and S. H. Simon, PRL 90 106802 (2003)), (I. Finkler, Y. Tserkovnyak, and S. H. Simon, work in progress.) that allows one to explicitly drag one particle around another and observe the change in the wavefunctions
Quantum Theory of Conducting Matter Superconductivity and Quantum Hall Effect
Fujita, Shigeji; Godoy, Salvador
2009-01-01
Explains major superconducting properties including zero resistance, Meissner effect, sharp phase change, flux quantization, excitation energy gap, and Josephson effects using quantum statistical mechanical calculations. This book covers the 2D superconductivity and the quantum Hall effects
Magnesium Hall Thruster for Solar System Exploration, Phase II
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...
W∞ gauge theory and the quantum Hall effect
International Nuclear Information System (INIS)
Shizuya, K.
1994-05-01
It is shown that a planar system of Hall electrons coupled to an applied electromagnetic field is written in the form of a W ∞ gauge theory. The associated W ∞ gauge field is expressed nonlinearly in terms of an infinite set of multipoles of the electromagnetic field. The W ∞ transformations generate mixing among the Landau levels. They provide a systematic way to classify the electromagnetic characteristics of the Hall system according to the resolution of external probes. In particular, an exact long-wavelength connection is derived between the carrier density and the Hall conductance in the presence of electron-electron interactions. Our approach is complementary to an earlier one and reveals a dual role the W ∞ gauge symmetry plays in the Hall dynamics. (author)
Magnetohydrodynamic simulations of Gamble I POS with Hall effect
International Nuclear Information System (INIS)
Roderick, N.F.; Frese, M.H.; Peterkin, R.E.; Payne, S.S.
1989-01-01
Two dimensional single fluid magnetohydrodynamic simulations have been conducted to investigate the effects of the Hall electric field on magnetic field transport in plasma opening switches of the type used on Gamble I. The Hall terms were included in the magnetic field transport equation in the two dimensional simulation code MACH2 through the use of a generalized Ohm's law. Calculations show the Hall terms augment the field transport previously observed to occur through ion fluid motion and diffusion. For modest values of microturbulent collision frequency, board current channels were observed . Results also show the magnetic field transport to be affected by the cathode boundary conditions with the Hall terms included. In all cases center of mass motion was slight
Observation of the anomalous Hall effect in GaAs
International Nuclear Information System (INIS)
Miah, M Idrish
2007-01-01
Devices for the direct detection of the spin current, based on the anomalous Hall effect (AHE), are fabricated on n-type GaAs bulk semiconductor materials. The AHE is observed in the device when the photoinduced spin-polarized electrons are injected into it, and it is found that the effect depends on the applied electric field. The origin of the field-dependent observed Hall effect is discussed based on the D'yakonov-Perel' (DP) spin relaxation mechanism. The spin-dependent Hall effect is also found to be enhanced with increasing doping concentration. The present experimental results might have potential applications in semiconductor spintronic devices since the effect is closely related to the spin Hall effect
Observation of the anomalous Hall effect in GaAs
Energy Technology Data Exchange (ETDEWEB)
Miah, M Idrish [Nanoscale Science and Technology Centre, School of Science, Griffith University, Nathan, Brisbane, QLD 4111 (Australia); Department of Physics, University of Chittagong, Chittagong, Chittagong - 4331 (Bangladesh)
2007-03-21
Devices for the direct detection of the spin current, based on the anomalous Hall effect (AHE), are fabricated on n-type GaAs bulk semiconductor materials. The AHE is observed in the device when the photoinduced spin-polarized electrons are injected into it, and it is found that the effect depends on the applied electric field. The origin of the field-dependent observed Hall effect is discussed based on the D'yakonov-Perel' (DP) spin relaxation mechanism. The spin-dependent Hall effect is also found to be enhanced with increasing doping concentration. The present experimental results might have potential applications in semiconductor spintronic devices since the effect is closely related to the spin Hall effect.
Nobel Prize in physics 1985: Quantum Hall effect
International Nuclear Information System (INIS)
Herrmann, R.
1986-01-01
The conditions (like very strong magnetic fields, ultralow temperatures, and occurrence of a two-dimensional electron gas in microelectronic structures) for the measurement of the quantum Hall effect are explained. Two possible measuring methods are described. Measuring results for p-Si-MOSFET, GaAs/AlGaAs heterojuntions and grain boundaries in InSb crystals are reported. Differences between normal (integer) and fractional quantum Hall effect are discussed. One of the important consequences is that by means of the quantum Hall effect the value h/e 2 can be determined with very high accuracy. In 1985 Klaus von Klitzing was awarded the Nobel Prize for his work on the quantum Hall effect
Quantum Computing With Quasiparticles of the Fractional Quantum Hall Effect
National Research Council Canada - National Science Library
Averin, Dmitri
2001-01-01
The focus of this project was the theoretical study of quantum computation based on controlled transfer of individual quasiparticles in systems of quantum antidots in the regime of the Fractional Quantum Hall Effect (FQHE...
Quantum Hall Ferroelectrics and Nematics in Multivalley Systems
Sodemann, Inti; Zhu, Zheng; Fu, Liang
2017-10-01
We study broken symmetry states at integer Landau-level fillings in multivalley quantum Hall systems whose low-energy dispersions are anisotropic. When the Fermi surface of individual pockets lacks twofold rotational symmetry, like in bismuth (111) [Feldman et al. , Observation of a Nematic Quantum Hall Liquid on the Surface of Bismuth, Science 354, 316 (2016), 10.1126/science.aag1715] and in Sn1 -xPbxSe (001) [Dziawa et al., Topological Crystalline Insulator States in Pb1 -xSnxSe , Nat. Mater. 11, 1023 (2012), 10.1038/nmat3449] surfaces, interactions tend to drive the formation of quantum Hall ferroelectric states. We demonstrate that the dipole moment in these states has an intimate relation to the Fermi surface geometry of the parent metal. In quantum Hall nematic states, like those arising in AlAs quantum wells, we demonstrate the existence of unusually robust Skyrmion quasiparticles.
Hall effects and related phenomena in disordered Rashba 2DEG
International Nuclear Information System (INIS)
Inoue, Jun-ichiro; Kato, Takashi; Bauer, Gerrit E W; Molenkamp, Laurens W
2009-01-01
We review our recent work on the spin and anomalous Hall effects and other related phenomena caused by the intrinsic spin–orbit interaction. We focus our attention on disorder effects on these transport properties by adopting a model of a two-dimensional electron gas with a Rashba-type spin–orbit interaction. A spin-polarized model is adopted to calculate the anomalous Hall effect and anisotropic magnetoresistance. It is shown that the spin Hall conductivity in the ballistic transport regime is cancelled by the so-called vertex corrections for the disorder scattering, and that the anomalous Hall conductivity and anisotropic magnetoresistance vanish unless the lifetime is spin dependent. We further present results on spin accumulation under an electric field
Dual Mode Low Power Hall Thruster, Phase I
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...
Suitable reverberation time for halls for rock and pop music
DEFF Research Database (Denmark)
Adelman-Larsen, Niels Werner; Thompson, Eric Robert; Gade, Anders Christian
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....... 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 m3. 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....
Analysis of Hall Probe Precise Positioning with Cylindrical Permanent Magnet
International Nuclear Information System (INIS)
Belicev, P.; Vorozhtsov, A.S.; Vorozhtsov, S.B.
2007-01-01
Precise positioning of a Hall probe for cyclotron magnetic field mapping, using cylindrical permanent magnets, was analyzed. The necessary permanent magnet parameters in order to achieve ±20 μm position precision, were determined. (author)
High Input Voltage Hall Thruster Discharge Converter, Phase I
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...
Pragmatic data fusion uncertainty concerns: Tribute to Dave L. Hall
CSIR Research Space (South Africa)
Blasch, E
2016-07-01
Full Text Available Over the course of Dave Hall's career, he highlighted various concerns associated with the implementation of data fusion methods. Many of the issues included the role of uncertainty in data fusion, practical implementation of sensor fusion systems...
2D Electrostatic Potential Solver for Hall Thruster Simulation
National Research Council Canada - National Science Library
Koo, Justin W
2006-01-01
...) for Hall thruster simulation. It is based on a finite volume discretization of a current conservation equation where the electron current density is described by a Generalized Ohm's law description...
Precision of single-engage micro Hall effect measurements
DEFF Research Database (Denmark)
Henrichsen, Henrik Hartmann; Hansen, Ole; Kjær, Daniel
2014-01-01
Recently a novel microscale Hall effect measurement technique has been developed to extract sheet resistance (RS), Hall sheet carrier density (NHS) and Hall mobility (μH) from collinear micro 4-point probe measurements in the vicinity of an insulating boundary [1]. The technique measures in less...... than a minute directly the local transport properties, which enables in-line production monitoring on scribe line test pads [2]. To increase measurement speed and reliability, a method in which 4-point measurements are performed using two different electrode pitches has been developed [3......]. In this study we calculate the measurement error on RS, NHS and μH resulting from electrode position errors, probe placement, sample size and Hall signal magnitude. We show the relationship between measurement precision and electrode pitch, which is important when down-scaling the micro 4-point probe to fit...
Understanding traditional African healing
MOKGOBI, M.G.
2014-01-01
Traditional African healing has been in existence for many centuries yet many people still seem not to understand how it relates to God and religion/spirituality. Some people seem to believe that traditional healers worship the ancestors and not God. It is therefore the aim of this paper to clarify this relationship by discussing a chain of communication between the worshipers and the Almighty God. Other aspects of traditional healing namely types of traditional healers, training of tradition...
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.
Brand new hall in the main building
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...
Acoustics in Halls for Speech and Music
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.
Hall MHD reconnection in cometary magnetotail
International Nuclear Information System (INIS)
Jovanovic, Dusan; Shukla, Padma Kant; Morfill, Gregor
2005-01-01
The fine structure of cometary tails (swirls, loops and blobs) is studied in the framework of resistive magnetic reconnection without a guide field in a dusty plasma. For a high-beta plasma (β ∼ 1) consisting of electrons, ions, and immobile dust grains, a two-fluid description is used to study electromagnetic perturbations with the frequency below Ωi, propagating at an arbitrary angle, and including the effects of Hall current. A zero-order current associated with the anti-parallel magnetic configuration may exist even in the limit of zero plasma temperature in a dusty plasma due to a symmetry breaking between electrons and ions by dust grains that yields an E-vector x B-vector current. In the perturbed state, a new linear electromagnetic mode is found in dusty plasma which is evanescent below the Rao cut-off frequency and has the characteristic wavelength comparable to the ion skin depth, which enables the reconnection at short spatial scales. The role of the dust is found to be twofold, yielding a new mode outside of the current sheet and altering the continuity conditions at its edge by an inhomogeneous Doppler shift associated with the E-vector x B-vector current
Testing a Beverage and Fruit/Vegetable Education Intervention in a University Dining Hall.
Scourboutakos, Mary J; Mah, Catherine L; Murphy, Sarah A; Mazza, Frank N; Barrett, Nathanael; McFadden, Bill; L'Abbé, Mary R
2017-06-01
To test the effect of a nutrition intervention that included education and 2 labeling components on students' food choices. Repeat cross-sectional study taking place on 6 dinner occasions before and 6 afterward. The study was conducted during dinner meals in a buffet-style dining hall in a university campus residence, where students paid a set price and consumed all they cared to eat. University students (n = 368 to 510) visited the cafeteria on each of the data collection dates. Fruit and vegetable consumption were encouraged; sugar-sweetened beverage consumption was discouraged using physical activity calorie equivalent labeling. Beverage choices and vegetable/fruit bar visits. Logistic regression was used to compare the proportion of student who selected each beverage, fruit, or vegetable before and after the intervention, while controlling for menu and gender as covariates. There was a significant decrease in the proportion of students selecting a sugar-sweetened beverage before vs after the intervention (49% vs 41%, respectively; P = .004) and an increase in students choosing water (43% vs 54%, respectively; P < .001). There was a significant increase in students who took fruit after the intervention (36%; P < .001) vs before (30%). The number of students visiting the vegetable bar significantly increased from 60% to 72% (P < .001). This intervention may be a way to encourage healthy dietary choices in campus dining halls. Copyright © 2017. Published by Elsevier Inc.
Linear waves in a resistive plasma with Hall current
International Nuclear Information System (INIS)
Almaguer, J.A.
1992-01-01
Dispersion relations for the case of a magnetized plasma are determined taking into account the Hall current and a constant resistivity, η, in Ohm's law. It is found that the Hall effect is relevant only for parallel (to the equilibrium magnetic field) wave numbers in the case of uniform plasmas, giving place to a dispersive behavior. In particular, the cases of η→0 and small (nonzero) resistivity are discussed
Hall effect in the two-dimensional Luttinger liquid
International Nuclear Information System (INIS)
Anderson, P.W.
1991-01-01
The temperature dependence of the Hall effect in the normal state is a commom theme of all the cuprate superconductors and has been one of the more puzzling observations on these puzzling materials. We describe a general scheme within the Luttinger liquid theory of these two-dimensional quantum fluids which corrrelates the anomalous Hall and resistivity observations on a wide variety of both pure and doped single crystals, especially the data in the accompanying Letter of Chien, Wang, and Ong
Thermoelectric and Hall-effect studies in hydrogenerated nickel foils
International Nuclear Information System (INIS)
Rani, R.; Nigam, A.N.
1978-01-01
Thermo e.m.f. and Hall constant of hydrogenerated nickel foils have been measured. Termo e.m.f. shows a sign reversal which is not due to the change in sign of the charge carriers, as indicated by the Hall-effect measurements. To account for the sign reversal of thermo e.m.f., it is found necessary to take into account the surface states of chemisorbed hydrogen on nickel
Fractional statistics and fractional quantized Hall effect. Revision
International Nuclear Information System (INIS)
Tao, R.; Wu, Y.S.
1984-01-01
We suggest that the origin of the odd denominator rule observed in the fractional quantized Hall effect (FQHE) may lie in fractional statistics which governs quasiparticles in FQHE. A theorem concerning statistics of clusters of quasiparticles implies that fractional statistics does not allow coexistence of a large number of quasiparticles at fillings with an even denominator. Thus no Hall plateau can be formed at these fillings, regardless of the presence of an energy gap. 15 references
Hall probe for measuring high currents in superconducting coils
International Nuclear Information System (INIS)
Ferendeci, A.M.
1986-01-01
Constructional details of a compact Hall probe for measuring high currents in superconducting coils are given. The Hall probe is easy to assemble and can be inserted or removed from the system without breaking the superconducting loop. Upper current limit of the probe can be increased by using larger magnetic core material. Shielding becomes necessary if the probe holder is to be placed near large current dependent magnetic fields
Low-Cost, High-Performance Hall Thruster Support System
Hesterman, Bryce
2015-01-01
Colorado Power Electronics (CPE) has built an innovative modular PPU for Hall thrusters, including discharge, magnet, heater and keeper supplies, and an interface module. This high-performance PPU offers resonant circuit topologies, magnetics design, modularity, and a stable and sustained operation during severe Hall effect thruster current oscillations. Laboratory testing has demonstrated discharge module efficiency of 96 percent, which is considerably higher than current state of the art.
Anonymity and Electronics: Adapting Preparation for Radiology Resident Examination.
Chapman, Teresa; Reid, Janet R; O'Conner, Erin E
2017-06-01
Diagnostic radiology resident assessment has evolved from a traditional oral examination to computerized testing. Teaching faculty struggle to reconcile the differences between traditional teaching methods and residents' new preferences for computerized testing models generated by new examination styles. We aim to summarize the collective experiences of senior residents at three different teaching hospitals who participated in case review sessions using a computer-based, interactive, anonymous teaching tool, rather than the Socratic method. Feedback was collected from radiology residents following participation in a senior resident case review session using Nearpod, which allows residents to anonymously respond to the teaching material. Subjective resident feedback was uniformly enthusiastic. Ninety percent of residents favor a case-based board review incorporating multiple-choice questions, and 94% favor an anonymous response system. Nearpod allows for inclusion of multiple-choice questions while also providing direct feedback to the teaching faculty, helping to direct the instruction and clarify residents' gaps in knowledge before the Core Examination. Copyright © 2017 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.
Anisotropic intrinsic spin Hall effect in quantum wires
International Nuclear Information System (INIS)
Cummings, A W; Akis, R; Ferry, D K
2011-01-01
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 [1-bar 10] 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. (paper)
The quantum Hall's effect: A quantum electrodynamic phenomenon
International Nuclear Information System (INIS)
Arbab, A. I.
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, V H = 2πħ 2 n s /em, where n s is the electron number density, for a 2-dimensional system, and h = 2πħ 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 L H = 2π m/e 2 n s and C H = me 2 /2πħ 2 n s satisfying the resonance condition with resonant frequency equal to the inverse of the scattering (relaxation) time, τ s . The Hall's resistance is found to be R H = √L H /C H . The Hall's resistance may be connected with the impedance that the electron wave experiences when it propagates in the 2-dimensional gas. (condensed matter: electronic structure, electrical, magnetic, and optical properties)
Signatures of lattice geometry in quantum and topological Hall effect
International Nuclear Information System (INIS)
Göbel, Börge; Mook, Alexander; Mertig, Ingrid; Henk, Jürgen
2017-01-01
The topological Hall effect (THE) of electrons in skyrmion crystals (SkXs) is strongly related to the quantum Hall effect (QHE) on lattices. This relation suggests to revisit the QHE because its Hall conductivity can be unconventionally quantized. It exhibits a jump and changes sign abruptly if the Fermi level crosses a van Hove singularity. In this Paper, we investigate the unconventional QHE features by discussing band structures, Hall conductivities, and topological edge states for square and triangular lattices; their origin are Chern numbers of bands in the SkX (THE) or of the corresponding Landau levels (QHE). Striking features in the energy dependence of the Hall conductivities are traced back to the band structure without magnetic field whose properties are dictated by the lattice geometry. Based on these findings, we derive an approximation that allows us to determine the energy dependence of the topological Hall conductivity on any two-dimensional lattice. The validity of this approximation is proven for the honeycomb lattice. We conclude that SkXs lend themselves for experiments to validate our findings for the THE and—indirectly—the QHE. (paper)
Tunnelling anomalous and planar Hall effects (Conference Presentation)
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).
A holographic model for the fractional quantum Hall effect
Energy Technology Data Exchange (ETDEWEB)
Lippert, Matthew [Institute for Theoretical Physics, University of Amsterdam,Science Park 904, 1090GL Amsterdam (Netherlands); Meyer, René [Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo,Kashiwa, Chiba 277-8568 (Japan); Taliotis, Anastasios [Theoretische Natuurkunde, Vrije Universiteit Brussel andThe International Solvay Institutes,Pleinlaan 2, B-1050 Brussels (Belgium)
2015-01-08
Experimental data for fractional quantum Hall systems can to a large extent be explained by assuming the existence of a Γ{sub 0}(2) modular symmetry group commuting with the renormalization group flow and hence mapping different phases of two-dimensional electron gases into each other. Based on this insight, we construct a phenomenological holographic model which captures many features of the fractional quantum Hall effect. Using an SL(2,ℤ)-invariant Einstein-Maxwell-axio-dilaton theory capturing the important modular transformation properties of quantum Hall physics, we find dyonic diatonic black hole solutions which are gapped and have a Hall conductivity equal to the filling fraction, as expected for quantum Hall states. We also provide several technical results on the general behavior of the gauge field fluctuations around these dyonic dilatonic black hole solutions: we specify a sufficient criterion for IR normalizability of the fluctuations, demonstrate the preservation of the gap under the SL(2,ℤ) action, and prove that the singularity of the fluctuation problem in the presence of a magnetic field is an accessory singularity. We finish with a preliminary investigation of the possible IR scaling solutions of our model and some speculations on how they could be important for the observed universality of quantum Hall transitions.
A holographic model for the fractional quantum Hall effect
Lippert, Matthew; Meyer, René; Taliotis, Anastasios
2015-01-01
Experimental data for fractional quantum Hall systems can to a large extent be explained by assuming the existence of a Γ0(2) modular symmetry group commuting with the renormalization group flow and hence mapping different phases of two-dimensional electron gases into each other. Based on this insight, we construct a phenomenological holographic model which captures many features of the fractional quantum Hall effect. Using an -invariant Einstein-Maxwell-axio-dilaton theory capturing the important modular transformation properties of quantum Hall physics, we find dyonic diatonic black hole solutions which are gapped and have a Hall conductivity equal to the filling fraction, as expected for quantum Hall states. We also provide several technical results on the general behavior of the gauge field fluctuations around these dyonic dilatonic black hole solutions: we specify a sufficient criterion for IR normalizability of the fluctuations, demonstrate the preservation of the gap under the action, and prove that the singularity of the fluctuation problem in the presence of a magnetic field is an accessory singularity. We finish with a preliminary investigation of the possible IR scaling solutions of our model and some speculations on how they could be important for the observed universality of quantum Hall transitions.
DEFF Research Database (Denmark)
Christensen, Mette Krogh; O'Neill, Lotte; Hansen, Dorthe Høgh
2016-01-01
Background The majority of studies on prevalence and characteristics of residents in difficulty have been conducted in English-speaking countries and the existing literature may not reflect the prevalence and characteristics of residents in difficulty in other parts of the world such as the Scand...... in a healthcare system. From our perspective, further sociological and pedagogical investigations in educational cultures across settings and specialties could inform our understanding of and knowledge about pitfalls in residents’ and doctors’ socialization into the healthcare system....
Understanding traditional African healing.
Mokgobi, M G
2014-09-01
Traditional African healing has been in existence for many centuries yet many people still seem not to understand how it relates to God and religion/spirituality. Some people seem to believe that traditional healers worship the ancestors and not God. It is therefore the aim of this paper to clarify this relationship by discussing a chain of communication between the worshipers and the Almighty God. Other aspects of traditional healing namely types of traditional healers, training of traditional healers as well as the role of traditional healers in their communities are discussed. In conclusion, the services of traditional healers go far beyond the uses of herbs for physical illnesses. Traditional healers serve many roles which include but not limited to custodians of the traditional African religion and customs, educators about culture, counselors, social workers and psychologists.
Singer, Benjamin D.; Corbridge, Thomas C.; Schroedl, Clara J.; Wilcox, Jane E.; Cohen, Elaine R.; McGaghie, William C.; Wayne, Diane B.
2012-01-01
Introduction Prior research shows that gaps exist in internal medicine residents’ critical care knowledge and skills. The purpose of this study was to compare the bedside critical care competency of first-year residents who received a simulation-based educational intervention plus clinical training to third-year residents who received clinical training alone. Methods During their first three months of residency, a group of first-year residents completed a simulation-based educational intervention. A group of traditionally-trained third-year residents who did not receive simulation-based training served as a comparison group. Both groups were evaluated using a 20-item clinical skills assessment at the bedside of a patient receiving mechanical ventilation at the end of their medical intensive care unit rotation. Scores on the skills assessment were compared between groups. Results Simulator-trained first-year residents (n=40) scored significantly higher compared to traditionally-trained third-year residents (n=27) on the bedside assessment, 91.3% (95% CI 88.2% to 94.3%) vs. 80.9% (95% CI 76.8% to 85.0%), P = simulation-based educational intervention demonstrated higher clinical competency than third-year residents who did not undergo simulation training. Critical care competency cannot be assumed after clinical ICU rotations; simulation-based curricula can help ensure residents are proficient to care for critically ill patients. PMID:23222546
Surface and 3D Quantum Hall Effects from Engineering of Exceptional Points in Nodal-Line Semimetals
Molina, Rafael A.; González, José
2018-04-01
We show that, under a strong magnetic field, a 3D nodal-line semimetal is driven into a topological insulating phase in which the electronic transport takes place at the surface of the material. When the magnetic field is perpendicular to the nodal ring, the surface states of the semimetal are transmuted into Landau states which correspond to exceptional points, i.e., branch points in the spectrum of a non-Hermitian Hamiltonian which arise upon the extension to complex values of the momentum. The complex structure of the spectrum then allows us to express the number of zero-energy flat bands in terms of a new topological invariant counting the number of exceptional points. When the magnetic field is parallel to the nodal ring, we find that the bulk states are built from the pairing of surfacelike evanescent waves, giving rise to a 3D quantum Hall effect with a flat level of Landau states residing in parallel 2D slices of the 3D material. The Hall conductance is quantized in either case in units of e2/h , leading in the 3D Hall effect to a number of channels growing linearly with the section of the surface and opening the possibility to observe a macroscopic chiral current at the surface of the material.
Simulation-based education with mastery learning improves residents' lumbar puncture skills
Cohen, Elaine R.; Caprio, Timothy; McGaghie, William C.; Simuni, Tanya; Wayne, Diane B.
2012-01-01
Objective: To evaluate the effect of simulation-based mastery learning (SBML) on internal medicine residents' lumbar puncture (LP) skills, assess neurology residents' acquired LP skills from traditional clinical education, and compare the results of SBML to traditional clinical education. Methods: This study was a pretest-posttest design with a comparison group. Fifty-eight postgraduate year (PGY) 1 internal medicine residents received an SBML intervention in LP. Residents completed a baseline skill assessment (pretest) using a 21-item LP checklist. After a 3-hour session featuring deliberate practice and feedback, residents completed a posttest and were expected to meet or exceed a minimum passing score (MPS) set by an expert panel. Simulator-trained residents' pretest and posttest scores were compared to assess the impact of the intervention. Thirty-six PGY2, 3, and 4 neurology residents from 3 medical centers completed the same simulated LP assessment without SBML. SBML posttest scores were compared to neurology residents' baseline scores. Results: PGY1 internal medicine residents improved from a mean of 46.3% to 95.7% after SBML (p < 0.001) and all met the MPS at final posttest. The performance of traditionally trained neurology residents was significantly lower than simulator-trained residents (mean 65.4%, p < 0.001) and only 6% met the MPS. Conclusions: Residents who completed SBML showed significant improvement in LP procedural skills. Few neurology residents were competent to perform a simulated LP despite clinical experience with the procedure. PMID:22675080
Habitat restoration/enhancement Fort Hall Reservation : 2001 annual report
International Nuclear Information System (INIS)
Moser, David C.
2003-01-01
Habitat enhancement, protection and monitoring were the focus of the Resident Fisheries Program during 2001. Enhancement and protection included sloping, fencing and planting willows at sites on Diggie Creek, Clear Creek and Spring Creek. In addition, many previously constructed instream structures (rock barbs and wing dams) were repaired throughout the Fort Hall Indian Reservation (Reservation). In 2001, exclosure fences were erected on Diggie Creek (250 m barbed wire; (70 m jack), Wood Creek (500 m jack), Clear Creek (20 m jack), Ross Fork Creek (200 m jack), West Fork Creek (200 m jack)) and the Portneuf River (1 km barbed wire; 100 m jack). Jack and rail exclosure fences that had deteriorated over the past ten years were repaired at numerous areas throughout the Reservation. Physical sampling during 2001 included sediment and depth surveys (SADMS) in Big Jimmy Creek and Diggie Creek. SADMS, used to track changes in channel morphology and specifically track movements of silt through Bottoms stream systems were completed for eight and nine strata in the Big Jimmy and Diggie Creek, respectively. Baseline SADM data was collected in Diggie Creek to monitor the effects of bank sloping and revegetation on channel morphology and sediment levels through time. Water temperature was monitored (hourly) in Spring Creek, Clear Creek, Ross Fork Creek and Big Jimmy Creek. Biotic sampling included invertebrate sampling in the 200 and 300 series of Clear Creek. Fish population densities and biomass were sampled in Clear Creek 200 and 300 series. Sampling protocols were identical to methods used in past years. Numbers of fish in Clear Creek 300 series remained similar to 2000 while numbers of fish in Clear Creek 200 series dropped to near pre project levels. Salmonid fry densities were monitored near Broncho Bridge and were significantly higher than 2000. A mark-recapture study was initiated in spring 2001 to estimate numbers of spawning adults using the Head End of Spring Creek
Burnout Syndrome During Residency.
Turgut, Namigar; Karacalar, Serap; Polat, Cengiz; Kıran, Özlem; Gültop, Fethi; Kalyon, Seray Türkmen; Sinoğlu, Betül; Zincirci, Mehmet; Kaya, Ender
2016-10-01
The aim of this study is identified the degree of Burnout Syndrome (BOS) and find out its correlation with years of recidency and sociodemograpfic chareacteristics, training, sleeping habits, such as smoking and alcohol consumption. After approval from the Hospital Ethics Committee and obtaining informed consent, First, second, third, fourth and fifth year of recidency staff (n=127) working in our hospital were involved in this study. The standardized Maslach Burnout Inventory (MBI) was used in this study. Fifty six male (44.1%) and seventy one female (55.9%) residents were enroled in this study (Coranbach Alfa(α)=0.873). 57% of the first year residents smokes cigaret and 54% of them use alcohol. 2% of them gets one day off after hospital night shift, 61% of them suffers from disturbed sleep. 60% of them had been stated that they willingly selected their profession. 61% of them prefers talking to friends and 32% of them prefers shopping to overcome stress. There were statistical difference acording to years of recidency in MBI, Emotional Burnout (EB) and desensitisation scale (DS) points. EB scale points of the second year of residency group was statisticaly higher than fourth year of residency group. DS points of second year of residency group was also statisticaly higher than the third and fourth year of residency group. There was no statistical difference between any groups in Personal Success. BOS is a frequent problem during residency in anaesthesia. Appropriate definition and awareness are the first important steps to prevent this syndrome. Further administrative approaches should be evaluated with regard to their effects.
DISK FORMATION IN MAGNETIZED CLOUDS ENABLED BY THE HALL EFFECT
International Nuclear Information System (INIS)
Krasnopolsky, Ruben; Shang, Hsien; Li Zhiyun
2011-01-01
Stars form in dense cores of molecular clouds that are observed to be significantly magnetized. A dynamically important magnetic field presents a significant obstacle to the formation of protostellar disks. Recent studies have shown that magnetic braking is strong enough to suppress the formation of rotationally supported disks in the ideal MHD limit. Whether non-ideal MHD effects can enable disk formation remains unsettled. We carry out a first study on how disk formation in magnetic clouds is modified by the Hall effect, the least explored of the three non-ideal MHD effects in star formation (the other two being ambipolar diffusion and Ohmic dissipation). For illustrative purposes, we consider a simplified problem of a non-self-gravitating, magnetized envelope collapsing onto a central protostar of fixed mass. We find that the Hall effect can spin up the inner part of the collapsing flow to Keplerian speed, producing a rotationally supported disk. The disk is generated through a Hall-induced magnetic torque. Disk formation occurs even when the envelope is initially non-rotating, provided that the Hall coefficient is large enough. When the magnetic field orientation is flipped, the direction of disk rotation is reversed as well. The implication is that the Hall effect can in principle produce both regularly rotating and counter-rotating disks around protostars. The Hall coefficient expected in dense cores is about one order of magnitude smaller than that needed for efficient spin-up in these models. We conclude that the Hall effect is an important factor to consider in studying the angular momentum evolution of magnetized star formation in general and disk formation in particular.
Changes in medicine: residency
Directory of Open Access Journals (Sweden)
Robbins RA
2011-07-01
Full Text Available No abstract available. Article truncated at 150 words. The most important time in a physician’s educational development is residency, especially the first year. However, residency work and responsibility have come under the scrutiny of a host of agencies and bureaucracies, and therefore, is rapidly changing. Most important in the alphabet soup of regulatory agencies is the Accreditation Council for Graduate Medical Education (ACGME which accredits residencies and ultimately makes the governing rules.Resident work hours have received much attention and are clearly decreasing. However, the decline in work hours began in the 1970’s before the present political push to decrease work hours. The residency I entered in 1976 had every third night call during the first year resident’s 6-9 months on general medicine or wards. It had changed from every other night the year before. On wards, we normally were in the hospital for our 24 hours of call and followed this with a 10-12 hour day before …
Neuroscience and humanistic psychiatry: a residency curriculum.
Griffith, James L
2014-04-01
Psychiatry residencies with a commitment to humanism commonly prioritize training in psychotherapy, cultural psychiatry, mental health policy, promotion of human rights, and similar areas reliant upon dialogue and collaborative therapeutic relationships. The advent of neuroscience as a defining paradigm for psychiatry has challenged residencies with a humanistic focus due to common perceptions that it would entail constriction of psychiatric practice to diagnostic and psychopharmacology roles. The author describes a neuroscience curriculum that has taught psychopharmacology effectively, while also advancing effectiveness of language-based and relationship-based therapeutics. In 2000, the George Washington University psychiatry residency initiated a neuroscience curriculum consisting of (1) a foundational postgraduate year 2 seminar teaching cognitive and social neuroscience and its integration into clinical psychopharmacology, (2) advanced seminars that utilized a neuroscience perspective in teaching specific psychotherapeutic skill sets, and (3) case-based teaching in outpatient clinical supervisions that incorporated a neuroscience perspective into traditional psychotherapy supervisions. Curricular assessment was conducted by (1) RRC reaccreditation site visit feedback, (2) examining career trajectories of residency graduates, (3) comparing PRITE exam Somatic Treatments subscale scores for 2010-2012 residents with pre-implementation residents, and (4) postresidency survey assessment by 2010-2012 graduates. The 2011 RRC site visit report recommended a "notable practice" citation for "innovative neurosciences curriculum." Three of twenty 2010-2012 graduates entered neuroscience research fellowships, as compared to none before the new curriculum. PRITE Somatic Treatments subscale scores improved from the 23rd percentile to the 62nd percentile in pre- to post-implementation of curriculum (p neuroscience curriculum for a residency committed to humanistic psychiatry
Hospital Medicine Resident Training Tracks: Developing the Hospital Medicine Pipeline.
Sweigart, Joseph R; Tad-Y, Darlene; Kneeland, Patrick; Williams, Mark V; Glasheen, Jeffrey J
2017-03-01
Hospital medicine (HM) is rapidly evolving into new clinical and nonclinical roles. Traditional internal medicine (IM) residency training likely does not optimally prepare residents for success in HM. Hospital medicine residency training tracks may offer a preferred method for specialized HM education. Internet searches and professional networks were used to identify HM training tracks. Information was gathered from program websites and discussions with track directors. The 11 HM tracks at academic medical centers across the United States focus mostly on senior residents. Track structure and curricular content are determined largely by the structure and curricula of the IM residency programs in which they exist. Almost all tracks feature experiential quality improvement projects. Content on healthcare economics and value is common, and numerous track leaders report this content is expanding from HM tracks into entire residency programs. Tracks also provide opportunities for scholarship and professional development, such as workshops on abstract creation and job procurement skills. Almost all tracks include HM preceptorships as well as rotations within various disciplines of HM. HM residency training tracks focus largely on quality improvement, health care economics, and professional development. The structures and curricula of these tracks are tightly linked to opportunities within IM residency programs. As HM continues to evolve, these tracks likely will expand to bridge clinical and extra-clinical gaps between traditional IM training and contemporary HM practice. Journal of Hospital Medicine 2017;12:173-176. © 2017 Society of Hospital Medicine
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.
G. Stanley Hall, Child Study, and the American Public.
Young, Jacy L
2016-01-01
In the final decades of the 19th century psychologist Granville Stanley Hall was among the most prominent pedagogical experts in the nation. The author explores Hall's carefully crafted persona as an educational expert, and his engagements with the American public, from 1880 to 1900, arguably the height of his influence. Drawing from accounts of Hall's lecture circuit in the popular press, a map of his talks across the nation is constructed to assess the geographic scope of his influence. These talks to educators on the psychology underlying childhood and pedagogy, and his views and research on child life more generally, were regularly discussed in newspapers and popular periodicals. The venues in which Hall's ideas were disseminated, discussed, and in some cases, dismissed are described. His efforts to mobilize popular support for, and assistance with, his research endeavors in child study are also discussed. Such efforts were controversial both within the burgeoning field of psychology and among the public. Through his various involvements in pedagogy, and concerted efforts to engage with the American public, Hall helped establish psychology's relevance to parenting and educational practices.
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
Emergency Medicine Resident Perceptions of Medical Professionalism
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Joshua Jauregui
2016-05-01
Full Text Available Introduction: Medical professionalism is a core competency for emergency medicine (EM trainees; but defining professionalism remains challenging, leading to difficulties creating objectives and performing assessment. Because professionalism is dynamic, culture-specific, and often taught by modeling, an exploration of trainees’ perceptions can highlight their educational baseline and elucidate the importance they place on general conventional professionalism domains. To this end, our objective was to assess the relative value EM residents place on traditional components of professionalism. Methods: We performed a cross-sectional, multi-institutional survey of incoming and graduating EM residents at four programs. The survey was developed using the American Board of Internal Medicine’s “Project Professionalism” and the Accreditation Council of Graduate Medical Education definition of professionalism competency. We identified 27 attributes within seven domains: clinical excellence, humanism, accountability, altruism, duty and service, honor and integrity, and respect for others. Residents were asked to rate each attribute on a 10-point scale. We analyzed data to assess variance across attributes as well as differences between residents at different training levels or different institutions. Results: Of the 114 residents eligible, 100 (88% completed the survey. The relative value assigned to different professional attributes varied considerably, with those in the altruism domain valued significantly lower and those in the “respect for others” and “honor and integrity” valued significantly higher (p<0.001. Significant differences were found between interns and seniors for five attributes primarily in the “duty and service” domain (p<0.05. Among different residencies, significant differences were found with attributes within the “altruism” and “duty and service” domains (p<0.05. Conclusion: Residents perceive differences in
Hall Measurements on Carbon Nanotube Paper Modified With Electroless Deposited Platinum
Directory of Open Access Journals (Sweden)
Iwuoha Emmanuel
2009-01-01
Full Text Available Abstract Carbon nanotube paper, sometimes referred to as bucky paper, is a random arrangement of carbon nanotubes meshed into a single robust structure, which can be manipulated with relative ease. Multi-walled carbon nanotubes were used to make the nanotube paper, and were subsequently modified with platinum using an electroless deposition method based on substrate enhanced electroless deposition. This involves the use of a sacrificial metal substrate that undergoes electro-dissolution while the platinum metal deposits out of solution onto the nanotube paper via a galvanic displacement reaction. The samples were characterized using SEM/EDS, and Hall-effect measurements. The SEM/EDS analysis clearly revealed deposits of platinum (Pt distributed over the nanotube paper surface, and the qualitative elemental analysis revealed co-deposition of other elements from the metal substrates used. When stainless steel was used as sacrificial metal a large degree of Pt contamination with various other metals was observed. Whereas when pure sacrificial metals were used bimetallic Pt clusters resulted. The co-deposition of a bimetallic system upon carbon nanotubes was a function of the metal type and the time of exposure. Hall-effect measurements revealed some interesting fluctuations in sheet carrier density and the dominant carrier switched from N- to P-type when Pt was deposited onto the nanotube paper. Perspectives on the use of the nanotube paper as a replacement to traditional carbon cloth in water electrolysis systems are also discussed.
A New Method for Analyzing Near-Field Faraday Probe Data in Hall Thrusters
Huang, Wensheng; Shastry, Rohit; Herman, Daniel A.; Soulas, George C.; Kamhawi, Hani
2013-01-01
This paper presents a new method for analyzing near-field Faraday probe data obtained from Hall thrusters. Traditional methods spawned from far-field Faraday probe analysis rely on assumptions that are not applicable to near-field Faraday probe data. In particular, arbitrary choices for the point of origin and limits of integration have made interpretation of the results difficult. The new method, called iterative pathfinding, uses the evolution of the near-field plume with distance to provide feedback for determining the location of the point of origin. Although still susceptible to the choice of integration limits, this method presents a systematic approach to determining the origin point for calculating the divergence angle. The iterative pathfinding method is applied to near-field Faraday probe data taken in a previous study from the NASA-300M and NASA-457Mv2 Hall thrusters. Since these two thrusters use centrally mounted cathodes the current density associated with the cathode plume is removed before applying iterative pathfinding. A procedure is presented for removing the cathode plume. The results of the analysis are compared to far-field probe analysis results. This paper ends with checks on the validity of the new method and discussions on the implications of the results.
Trends in preference, programming and design of concert halls for symphonic music
DEFF Research Database (Denmark)
Gade, Anders Christian
2008-01-01
This paper discusses the evolution in taste regarding concert hall acoustics and how this can be reflected in the new halls being built today. The clients' and listener's preferences are not only based on listening in existing halls; but also on listening to reproduced music recorded with microph......This paper discusses the evolution in taste regarding concert hall acoustics and how this can be reflected in the new halls being built today. The clients' and listener's preferences are not only based on listening in existing halls; but also on listening to reproduced music recorded...
Modular invariance, universality and crossover in the quantum Hall effect
International Nuclear Information System (INIS)
Dolan, Brian P.
1999-01-01
An analytic form for the conductivity tensor in crossover between two quantum Hall plateaux is derived, which appears to be in good agreement with existing experimental data. The derivation relies on an assumed symmetry between quantum Hall states, a generalisation of the law of corresponding states from rational filling factors to complex conductivity, which has a mathematical expression in terms of an action of the modular group on the upper-half complex conductivity plane. This symmetry implies universality in quantum Hall crossovers. The assumption that the β-function for the complex conductivity is a complex analytic function, together with some experimental constraints, results in an analytic expression for the crossover, as a function of the external magnetic field
Carl Gustav Jung and Granville Stanley Hall on Religious Experience.
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.
Admittance of multiterminal quantum Hall conductors at kilohertz frequencies
International Nuclear Information System (INIS)
Hernández, C.; Consejo, C.; Chaubet, C.; Degiovanni, P.
2014-01-01
We present an experimental study of the low frequency admittance of quantum Hall conductors in the [100 Hz, 1 MHz] frequency range. We show that the frequency dependence of the admittance of the sample strongly depends on the topology of the contacts connections. Our experimental results are well explained within the Christen and Büttiker approach for finite frequency transport in quantum Hall edge channels taking into account the influence of the coaxial cables capacitance. In the Hall bar geometry, we demonstrate that there exists a configuration in which the cable capacitance does not influence the admittance measurement of the sample. In this case, we measure the electrochemical capacitance of the sample and observe its dependence on the filling factor
Admittance of multiterminal quantum Hall conductors at kilohertz frequencies
Energy Technology Data Exchange (ETDEWEB)
Hernández, C. [Departamento de Física, Universidad Militar Nueva Granada, Carrera 11 101-80 Bogotá D.C. (Colombia); Consejo, C.; Chaubet, C., E-mail: christophe.chaubet@univ-montp2.fr [Université Montpellier 2, Laboratoire Charles Coulomb UMR5221, F-34095 Montpellier, France and CNRS, Laboratoire Charles Coulomb UMR5221, F-34095 Montpellier (France); Degiovanni, P. [Université de Lyon, Fédération de Physique Andrée Marie Ampère, CNRS, Laboratoire de Physique de l' Ecole Normale Supérieure de Lyon, 46 allée d' Italie, 69364 Lyon Cedex 07 (France)
2014-03-28
We present an experimental study of the low frequency admittance of quantum Hall conductors in the [100 Hz, 1 MHz] frequency range. We show that the frequency dependence of the admittance of the sample strongly depends on the topology of the contacts connections. Our experimental results are well explained within the Christen and Büttiker approach for finite frequency transport in quantum Hall edge channels taking into account the influence of the coaxial cables capacitance. In the Hall bar geometry, we demonstrate that there exists a configuration in which the cable capacitance does not influence the admittance measurement of the sample. In this case, we measure the electrochemical capacitance of the sample and observe its dependence on the filling factor.
Crossover between spin swapping and Hall effect in disordered systems
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.
The quantum Hall effect in quantum dot systems
International Nuclear Information System (INIS)
Beltukov, Y M; Greshnov, A A
2014-01-01
It is proposed to use quantum dots in order to increase the temperatures suitable for observation of the integer quantum Hall effect. A simple estimation using Fock-Darwin spectrum of a quantum dot shows that good part of carriers localized in quantum dots generate the intervals of plateaus robust against elevated temperatures. Numerical calculations employing local trigonometric basis and highly efficient kernel polynomial method adopted for computing the Hall conductivity reveal that quantum dots may enhance peak temperature for the effect by an order of magnitude, possibly above 77 K. Requirements to potentials, quality and arrangement of the quantum dots essential for practical realization of such enhancement are indicated. Comparison of our theoretical results with the quantum Hall measurements in InAs quantum dot systems from two experimental groups is also given
Diaphragm Effect of Steel Space Roof Systems in Hall Structures
Directory of Open Access Journals (Sweden)
Mehmet FENKLİ
2015-09-01
Full Text Available Hall structures have been used widely for different purposes. They have are reinforced concrete frames and shear wall with steel space roof systems. Earthquake response of hall structures is different from building type structures. One of the most critical nodes is diaphragm effect of steel space roof on earthquake response of hall structures. Diaphragm effect is depending on lateral stiffness capacity of steel space roof system. Lateral stiffness of steel space roof system is related to modulation geometry, support conditions, selected sections and system geometry. In current paper, three representative models which are commonly used in Turkey were taken in to account for investigation. Results of numerical tests were present comparatively
Novel Hall sensors developed for magnetic field imaging systems
International Nuclear Information System (INIS)
Cambel, Vladimir; Karapetrov, Goran; Novosad, Valentyn; Bartolome, Elena; Gregusova, Dagmar; Fedor, Jan; Kudela, Robert; Soltys, Jan
2007-01-01
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
Crossover between spin swapping and Hall effect in disordered systems
Saidaoui, Hamed Ben Mohamed; Otani, Y.; Manchon, Aurelien
2015-01-01
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.
ε-iron nitrides: Intrinsic anomalous Hall ferromagnets
Directory of Open Access Journals (Sweden)
Guo-Ke Li
2015-02-01
Full Text Available The anomalous Hall effect in ε-iron nitrides (ε-Fe3-xN, 0 ≤ x ≤ 1 has been systematically investigated taking advantage of the fact that the exchange splitting of ε-Fe3-xN can be continuously tuned through the nitrogen concentration. It has been found that the anomalous Hall conductivity, σ x y A H , is proportional to the saturation magnetization MS, i.e., σ x y A H = S H M S , across significant variations in the saturation magnetization (96–1146 emu/cc. This relationship is in excellent agreement with the intrinsic mechanism as well as with the unified theory of AHE. Our results also demonstrate that the anomalous Hall conductivity is sensitive to the exchange splitting of the band structure.
Overview of NASA Iodine Hall Thruster Propulsion System Development
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.
Resident fatigue in otolaryngology residents: a Web based survey.
Nida, Andrew M; Googe, Benjamin J; Lewis, Andrea F; May, Warren L
2016-01-01
Resident fatigue has become a point of emphasis in medical education and its effects on otolaryngology residents and their patients require further study. The purpose of our study was to evaluate the prevalence and nature of fatigue in otolaryngology residents, evaluate various quality of life measures, and investigate associations of increased fatigue with resident safety. Anonymous survey. Internet based. United States allopathic otolaryngology residents. None. The survey topics included demographics, residency structure, sleep habits and perceived stress. Responses were correlated with a concurrent Epworth Sleep Scale questionnaire to evaluate effects of fatigue on resident training and quality of life. 190 residents responded to the survey with 178 completing the Epworth Sleep Scale questionnaire. Results revealed a mean Epworth Sleep Scale score of 9.9±5.1 with a median of 10.0 indicating a significant number of otolaryngology residents are excessively sleepy. Statistically significant correlations between Epworth Sleep Scale and sex, region, hours of sleep, and work hours were found. Residents taking in-house call had significantly fewer hours of sleep compared to home call (p=0.01). Residents on "head and neck" (typically consisting of a large proportion of head and neck oncologic surgery) rotations tended to have higher Epworth Sleep Scale and had significantly fewer hours of sleep (p=.003) and greater work hours (potolaryngology residents are excessively sleepy. Our data suggest that the effects of fatigue play a role in resident well-being and resident safety. Copyright © 2016 Elsevier Inc. All rights reserved.
International Nuclear Information System (INIS)
Martin, L. N.; Dmitruk, P.; Gomez, D. O.
2010-01-01
In this work we numerically test a model of Hall magnetohydrodynamics in the presence of a strong mean magnetic field: the reduced Hall magnetohydrodynamic model (RHMHD) derived by [Gomez et al., Phys. Plasmas 15, 102303 (2008)] with the addition of weak compressible effects. The main advantage of this model lies in the reduction of computational cost. Nevertheless, up until now the degree of agreement with the original Hall MHD system and the range of validity in a regime of turbulence were not established. In this work direct numerical simulations of three-dimensional Hall MHD turbulence in the presence of a strong mean magnetic field are compared with simulations of the weak compressible RHMHD model. The results show that the degree of agreement is very high (when the different assumptions of RHMHD, such as spectral anisotropy, are satisfied). Nevertheless, when the initial conditions are isotropic but the mean magnetic field is maintained strong, the results differ at the beginning but asymptotically reach a good agreement at relatively short times. We also found evidence that the compressibility still plays a role in the dynamics of these systems, and the weak compressible RHMHD model is able to capture these effects. In conclusion the weak compressible RHMHD model is a valid approximation of the Hall MHD turbulence in the relevant physical context.
Spin-Hall nano-oscillator: A micromagnetic study
Energy Technology Data Exchange (ETDEWEB)
Giordano, A.; Azzerboni, B.; Finocchio, G. [Department of Electronic Engineering, Industrial Chemistry and Engineering, University of Messina, C.da di Dio, I-98166 Messina (Italy); Carpentieri, M. [Department of Electrical and Information Engineering, Politecnico of Bari, via E. Orabona 4, I-70125 Bari (Italy); Laudani, A. [Department of Engineering, University of Roma Tre, via V. Volterra 62, I-00146 Roma (Italy); Gubbiotti, G. [Istituto Officina dei Materiali del CNR (CNR-IOM), Unità di Perugia c/o Dipartimento di Fisica e Geologia, Via A. Pascoli, 06123 Perugia (Italy)
2014-07-28
This Letter studies the dynamical behavior of spin-Hall nanoscillators from a micromagnetic point of view. The model parameters have been identified by reproducing recent experimental data quantitatively. Our results indicate that a strongly localized mode is observed for in-plane bias fields such as in the experiments, while predict the excitation of an asymmetric propagating mode for large enough out-of plane bias field similarly to what observed in spin-torque nanocontact oscillators. Our findings show that spin-Hall nanoscillators can find application as spin-wave emitters for magnonic applications where spin waves are used for transmission and processing information on nanoscale.
Complex scattering dynamics and the quantum Hall effects
International Nuclear Information System (INIS)
Trugman, S.A.
1994-01-01
We review both classical and quantum potential scattering in two dimensions in a magnetic field, with applications to the quantum Hall effect. Classical scattering is complex, due to the approach of scattering states to an infinite number of dynamically bound states. Quantum scattering follows the classical behavior rather closely, exhibiting sharp resonances in place of the classical bound states. Extended scatterers provide a quantitative explanation for the breakdown of the QHE at a comparatively small Hall voltage as seen by Kawaji et al., and possibly for noise effects
Impact of external conditions on energy consumption in industrial halls
Żabnieńśka-Góra, Alina
2017-11-01
The energy demand for heating the halls buildings is high. The impact on this may have the technology of production, building construction and technology requirements (HVAC systems). The isolation of the external partitions, the location of the object in relation to the surrounding buildings and the degree of the interior insolation (windows and skylights) are important in the context of energy consumption. The article discusses the impact of external conditions, wind and sunlight on energy demand in the industrial hall. The building model was prepared in IDA ICE 4.0 simulation software. Model validation was done based on measurements taken in the analyzed building.
Hall effects on MHD flow past an accelerated plate
Directory of Open Access Journals (Sweden)
Deka R.K.
2008-01-01
Full Text Available The simultaneous effects of rotation and Hall current on the hydromagnetic flow past an accelerated horizontal plate relative to a rotating fluid is presented. It is found that for given values of m (Hall parameter, M (Hartmann number and an imposed rotation parameter Ω satisfying Ω = M 2m/(1 + m2, the transverse motion (transverse to the main flow disappears and the fluid moves in the direction of the plate only. The effects of the parameters m, M and Ω on the axial and transverse velocity profiles are shown graphically, whereas the effects of the parameters on the skin-friction components are shown by tabular values.
Spectroscopy of snake states using a graphene Hall bar
Energy Technology Data Exchange (ETDEWEB)
Milovanović, S. P., E-mail: slavisa.milovanovic@gmail.com; Ramezani Masir, M., E-mail: mrmphys@gmail.com; Peeters, F. M., E-mail: francois.peeters@ua.ac.be [Departement Fysica, Universiteit Antwerpen, Groenenborgerlaan 171, B-2020 Antwerpen (Belgium)
2013-12-02
An approach to observe snake states in a graphene Hall bar containing a pn-junction is proposed. The magnetic field dependence of the bend resistance in a ballistic graphene Hall bar structure containing a tilted pn-junction oscillates as a function of applied magnetic field. We show that each oscillation is due to a specific snake state that moves along the pn-interface. Furthermore, depending on the value of the magnetic field and applied potential, we can control the lead in which the electrons will end up and hence control the response of the system.
Theory of spin Hall effect: extension of the Drude model.
Chudnovsky, Eugene M
2007-11-16
An extension of the Drude model is proposed that accounts for the spin and spin-orbit interaction of charge carriers. Spin currents appear due to the combined action of the external electric field, crystal field, and scattering of charge carriers. The expression for the spin Hall conductivity is derived for metals and semiconductors that is independent of the scattering mechanism. In cubic metals, the spin Hall conductivity sigma s and charge conductivity sigma c are related through sigma s=[2pi variant /(3mc2)]sigma2c with m being the bare electron mass. The theoretically computed value is in agreement with experiment.
Hall measurements and grain-size effects in polycrystalline silicon
International Nuclear Information System (INIS)
Ghosh, A.K.; Rose, A.; Maruska, H.P.; Eustace, D.J.; Feng, T.
1980-01-01
The effects of grain size on Hall measurements in polycrystalline silicon are analyzed and interpreted, with some modifications, using the model proposed by Bube. This modified model predicts that the measured effective Hall voltage is composed of components originating from the bulk and space-charge regions. For materials with large grain sizes, the carrier concentration is independent of the intergrain boundary barrier, whereas the mobility is dependent on it. However, for small grains, both the carrier density and mobility depend on the barrier. These predictions are consistent with experimental results of mm-size Wacker and μm-size neutron-transmutation-doped polycrystalline silicon
Fractional quantum Hall states of atoms in optical lattices
International Nuclear Information System (INIS)
Soerensen, Anders S.; Demler, Eugene; Lukin, Mikhail D.
2005-01-01
We describe a method to create fractional quantum Hall states of atoms confined in optical lattices. We show that the dynamics of the atoms in the lattice is analogous to the motion of a charged particle in a magnetic field if an oscillating quadrupole potential is applied together with a periodic modulation of the tunneling between lattice sites. In a suitable parameter regime the ground state in the lattice is of the fractional quantum Hall type, and we show how these states can be reached by melting a Mott-insulator state in a superlattice potential. Finally, we discuss techniques to observe these strongly correlated states
Theory of the quantized Hall effect. Pt. 3
International Nuclear Information System (INIS)
Levine, H.; Pruisken, A.M.M.; Libby, S.B.
1984-01-01
In the previous paper, we have demonstrated the need for a phase transition as a function of theta in the non-liner sigma-model describing the quantized Hall effect. In this work, we present arguments for the occurrence of exactly such a transition. We make use of a dilute gas instanton approximation as well as present a more rigorous duality argument to show that the usual scaling of the conductivity to zero at large distances is altered whenever sigmasub(xy)sup((0)) approx.= 1/2ne 2 /h, n integer. This then completes our theory of the quantized Hall effect. (orig.)
Complex dynamics of the integer quantum Hall effect
International Nuclear Information System (INIS)
Trugman, S.A.; Nicopoulos, V.N.; Florida Univ., Gainesville, FL
1991-01-01
We investigate both classical and quantum potential scattering in two dimensions in a magnetic field, with applications to the integer quantum Hall effect. Classical scattering is complex, due in one case to the approach of scattering states to an infinite number of bound states. We show that bound states are generic, and occur for all but extremely smooth scattering potentials (|rvec ∇| → 0). Quantum scattering follows the classical behavior rather closely, exhibiting sharp resonances rather than classical bound states. Extended scatterers provide an explanation for the breakdown of the QHE at a comparatively small Hall voltage. 16 refs., 14 figs
Spin Hall magnetoresistance in antiferromagnet/normal metal bilayers
Manchon, Aurelien
2017-01-01
We investigate the emergence of spin Hall magnetoresistance in a magnetic bilayer composed of a normal metal adjacent to an antiferromagnet. Based on a recently derived drift diffusion equation, we show that the resistance of the bilayer depends on the relative angle between the direction transverse to the current flow and the Néel order parameter. While this effect presents striking similarities with the spin Hall magnetoresistance recently reported in ferromagnetic bilayers, its physical origin is attributed to the anisotropic spin relaxation of itinerant spins in the antiferromagnet.
Quantum hall fluid on fuzzy two dimensional sphere
International Nuclear Information System (INIS)
Luo Xudong; Peng Dantao
2004-01-01
After reviewing the Haldane's description about the quantum Hall effect on the fuzzy two-sphere S 2 , authors construct the noncommutative algebra on the fuzzy sphere S 2 and the Moyal structure of the Hilbert space. By constructing noncommutative Chern-Simons theory of the incompressible Hall fluid on the fuzzy sphere and solving the Gaussian constraint with quasiparticle source, authors find the Calogero matrix on S 2 and the complete set of the Laughlin wave function for the lowest Landau level, and this wave function is expressed by the generalized Jack polynomials in terms of spinor coordinates. (author)
Bingo halls and smoking: perspectives of First Nations women.
Bottorff, Joan L; Carey, Joanne; Mowatt, Roberta; Varcoe, Colleen; Johnson, Joy L; Hutchinson, Peter; Sullivan, Debbie; Williams, Wanda; Wardman, Dennis
2009-12-01
The purpose of this study was to examine bingo halls as a frequent site for exposure to secondhand cigarette smoke for First Nations women in rural communities. Thematic analysis of interviews with key informants, group discussions with young women, and observations in the study communities revealed that smoky bingo halls provided an important refuge from everyday experiences of stress and trauma, as well as increased women's risk for addiction, marginalization, and criticism. The findings illustrate how the bingo economy in isolated, rural First Nation communities influences tobacco use and second-hand smoke exposure, and how efforts to establish smoke-free bingos can be supported.
Effect of Anode Dielectric Coating on Hall Thruster Operation
International Nuclear Information System (INIS)
Dorf, L.; Raitses, Y.; Fisch, N.J.; Semenov, V.
2003-01-01
An interesting phenomenon observed in the near-anode region of a Hall thruster is that the anode fall changes from positive to negative upon removal of the dielectric coating, which is produced on the anode surface during the normal course of Hall thruster operation. The anode fall might affect the thruster lifetime and acceleration efficiency. The effect of the anode coating on the anode fall is studied experimentally using both biased and emissive probes. Measurements of discharge current oscillations indicate that thruster operation is more stable with the coated anode
Magnetoresistance and Hall resistivity of semimetal WTe2 ultrathin flakes.
Luo, Xin; Fang, Chi; Wan, Caihua; Cai, Jialin; Liu, Yong; Han, Xiufeng; Lu, Zhihong; Shi, Wenhua; Xiong, Rui; Zeng, Zhongming
2017-04-07
This article reports the characterization of WTe 2 thin flake magnetoresistance and Hall resistivity. We found it does not exhibit magnetoresistance saturation when subject to high fields, in a manner similar to their bulk characteristics. The linearity of Hall resistivity in our devices confirms the compensation of electrons and holes. By relating experimental results to a classic two-band model, the lower magnetoresistance values in our samples is demonstrated to be caused by decreased carrier mobility. The dependence of mobility on temperature indicates the main role of optical phonon scattering at high temperatures. Our results provide more detailed information on carrier behavior and scattering mechanisms in WTe 2 thin films.
Measurement of the Hall effect in semiconductors at supersonic frequencies
International Nuclear Information System (INIS)
Putyato, I.V.; Sukhanov, S.; Lezhnev, N.B.
1978-01-01
A new method of measuring the Hall effect in variable magnetic fields at super-high frequencies using slotted line is proposed. The method is applied to the measurement of the Hall effect in n-InSb samples. It is shown that the level of output signal of samples reduces with the increasing the charge carrier concentration and with decreasing the mobility. But the range of quadratic part of the dependence of the output signal power on the control current increases. It is stated that the output signal of samples does not depend on the magnetic field frequency in the range of 4-7.3 GHz
Measurement of the Hall effect in semiconductors at supersonic frequencies
Energy Technology Data Exchange (ETDEWEB)
Putyato, I V; Sukhanov, S; Lezhnev, N B [AN Tadzhikskoj SSR, Khorog. Pamirskij Biologicheskij Inst.
1978-01-01
A new method of measuring the Hall effect in variable magnetic fields at super-high frequencies using slotted line is proposed. The method is applied to the measurement of the Hall effect in n-InSb samples. It is shown that the level of output signal of samples reduces with the increasing the charge carrier concentration and with decreasing the mobility. But the range of quadratic part of the dependence of the output signal power on the control current increases. It is stated that the output signal of samples does not depend on the magnetic field frequency in the range of 4-7.3 GHz.
Electrocardiographic interpretation skills of cardiology residents: are they competent?
Sibbald, Matthew; Davies, Edward G; Dorian, Paul; Yu, Eric H C
2014-12-01
Achieving competency at electrocardiogram (ECG) interpretation among cardiology subspecialty residents has traditionally focused on interpreting a target number of ECGs during training. However, there is little evidence to support this approach. Further, there are no data documenting the competency of ECG interpretation skills among cardiology residents, who become de facto the gold standard in their practice communities. We tested 29 Cardiology residents from all 3 years in a large training program using a set of 20 ECGs collected from a community cardiology practice over a 1-month period. Residents interpreted half of the ECGs using a standard analytic framework, and half using their own approach. Residents were scored on the number of correct and incorrect diagnoses listed. Overall diagnostic accuracy was 58%. Of 6 potentially life-threatening diagnoses, residents missed 36% (123 of 348) including hyperkalemia (81%), long QT (52%), complete heart block (35%), and ventricular tachycardia (19%). Residents provided additional inappropriate diagnoses on 238 ECGs (41%). Diagnostic accuracy was similar between ECGs interpreted using an analytic framework vs ECGs interpreted without an analytic framework (59% vs 58%; F(1,1333) = 0.26; P = 0.61). Cardiology resident proficiency at ECG interpretation is suboptimal. Despite the use of an analytic framework, there remain significant deficiencies in ECG interpretation among Cardiology residents. A more systematic method of addressing these important learning gaps is urgently needed. Copyright © 2014 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.
Results of a Flipped Classroom Teaching Approach in Anesthesiology Residents.
Martinelli, Susan M; Chen, Fei; DiLorenzo, Amy N; Mayer, David C; Fairbanks, Stacy; Moran, Kenneth; Ku, Cindy; Mitchell, John D; Bowe, Edwin A; Royal, Kenneth D; Hendrickse, Adrian; VanDyke, Kenneth; Trawicki, Michael C; Rankin, Demicha; Guldan, George J; Hand, Will; Gallagher, Christopher; Jacob, Zvi; Zvara, David A; McEvoy, Matthew D; Schell, Randall M
2017-08-01
In a flipped classroom approach, learners view educational content prior to class and engage in active learning during didactic sessions. We hypothesized that a flipped classroom improves knowledge acquisition and retention for residents compared to traditional lecture, and that residents prefer this approach. We completed 2 iterations of a study in 2014 and 2015. Institutions were assigned to either flipped classroom or traditional lecture for 4 weekly sessions. The flipped classroom consisted of reviewing a 15-minute video, followed by 45-minute in-class interactive sessions with audience response questions, think-pair-share questions, and case discussions. The traditional lecture approach consisted of a 55-minute lecture given by faculty with 5 minutes for questions. Residents completed 3 knowledge tests (pretest, posttest, and 4-month retention) and surveys of their perceptions of the didactic sessions. A linear mixed model was used to compare the effect of both formats on knowledge acquisition and retention. Of 182 eligible postgraduate year 2 anesthesiology residents, 155 (85%) participated in the entire intervention, and 142 (78%) completed all tests. The flipped classroom approach improved knowledge retention after 4 months (adjusted mean = 6%; P = .014; d = 0.56), and residents preferred the flipped classroom (pre = 46%; post = 82%; P flipped classroom approach to didactic education resulted in a small improvement in knowledge retention and was preferred by anesthesiology residents.
Mani, Arjun; Benjamin, Colin
2016-04-13
On the surface of 2D topological insulators, 1D quantum spin Hall (QSH) edge modes occur with Dirac-like dispersion. Unlike quantum Hall (QH) edge modes, which occur at high magnetic fields in 2D electron gases, the occurrence of QSH edge modes is due to spin-orbit scattering in the bulk of the material. These QSH edge modes are spin-dependent, and chiral-opposite spins move in opposing directions. Electronic spin has a larger decoherence and relaxation time than charge. In view of this, it is expected that QSH edge modes will be more robust to disorder and inelastic scattering than QH edge modes, which are charge-dependent and spin-unpolarized. However, we notice no such advantage accrues in QSH edge modes when subjected to the same degree of contact disorder and/or inelastic scattering in similar setups as QH edge modes. In fact we observe that QSH edge modes are more susceptible to inelastic scattering and contact disorder than QH edge modes. Furthermore, while a single disordered contact has no effect on QH edge modes, it leads to a finite charge Hall current in the case of QSH edge modes, and thus a vanishing of the pure QSH effect. For more than a single disordered contact while QH states continue to remain immune to disorder, QSH edge modes become more susceptible--the Hall resistance for the QSH effect changes sign with increasing disorder. In the case of many disordered contacts with inelastic scattering included, while quantization of Hall edge modes holds, for QSH edge modes a finite charge Hall current still flows. For QSH edge modes in the inelastic scattering regime we distinguish between two cases: with spin-flip and without spin-flip scattering. Finally, while asymmetry in sample geometry can have a deleterious effect in the QSH case, it has no impact in the QH case.
International Nuclear Information System (INIS)
Mani, Arjun; Benjamin, Colin
2016-01-01
On the surface of 2D topological insulators, 1D quantum spin Hall (QSH) edge modes occur with Dirac-like dispersion. Unlike quantum Hall (QH) edge modes, which occur at high magnetic fields in 2D electron gases, the occurrence of QSH edge modes is due to spin–orbit scattering in the bulk of the material. These QSH edge modes are spin-dependent, and chiral-opposite spins move in opposing directions. Electronic spin has a larger decoherence and relaxation time than charge. In view of this, it is expected that QSH edge modes will be more robust to disorder and inelastic scattering than QH edge modes, which are charge-dependent and spin-unpolarized. However, we notice no such advantage accrues in QSH edge modes when subjected to the same degree of contact disorder and/or inelastic scattering in similar setups as QH edge modes. In fact we observe that QSH edge modes are more susceptible to inelastic scattering and contact disorder than QH edge modes. Furthermore, while a single disordered contact has no effect on QH edge modes, it leads to a finite charge Hall current in the case of QSH edge modes, and thus a vanishing of the pure QSH effect. For more than a single disordered contact while QH states continue to remain immune to disorder, QSH edge modes become more susceptible—the Hall resistance for the QSH effect changes sign with increasing disorder. In the case of many disordered contacts with inelastic scattering included, while quantization of Hall edge modes holds, for QSH edge modes a finite charge Hall current still flows. For QSH edge modes in the inelastic scattering regime we distinguish between two cases: with spin-flip and without spin-flip scattering. Finally, while asymmetry in sample geometry can have a deleterious effect in the QSH case, it has no impact in the QH case. (paper)
Valley polarized quantum Hall effect and topological insulator phase transitions in silicene
Tahir, M.; Schwingenschlö gl, Udo
2013-01-01
encountered for graphene, in particular the zero band gap and weak spin orbit interaction. We demonstrate a valley polarized quantum Hall effect and topological insulator phase transitions. We use the Kubo formalism to discuss the Hall conductivity and address
Measured Early Lateral Energy Fractions in Concert Halls and Opera Houses
BARRON, M.
2000-04-01
In the 30 years since early lateral reflections were first suggested as important for concert halls, spatial impression and source broadening have become almost universally accepted as essential characteristics of halls with good acoustics. Two objective measures of source broadening have been proposed. Measured values of the best defined of these measures, the early lateral energy fraction (LF), are considered here. Results from two independent measurement surveys are discussed. Comparisons of LF values by hall show a significant link between hall mean LF and hall width. There is however considerable overlap between measured LF values in different halls so the relevance of describing halls by their mean early lateral energy fraction values is questionable. The behaviour of LF values within auditoria is discussed for different concert hall plan forms and within opera houses. A measure of source broadening including sound level is proposed and results considered in the context of auditorium design.
Leadership Training in Otolaryngology Residency.
Bent, John P; Fried, Marvin P; Smith, Richard V; Hsueh, Wayne; Choi, Karen
2017-06-01
Although residency training offers numerous leadership opportunities, most residents are not exposed to scripted leadership instruction. To explore one program's attitudes about leadership training, a group of otolaryngology faculty (n = 14) and residents (n = 17) was polled about their attitudes. In terms of self-perception, more faculty (10 of 14, 71.4%) than residents (9 of 17, 52.9%; P = .461) considered themselves good leaders. The majority of faculty and residents (27 of 31) thought that adults could be taught leadership ability. Given attitudes about leadership ability and the potential for improvement through instruction, consideration should be given to including such training in otolaryngology residency.
A novel adjuvant to the resident selection process: the hartman value profile.
Cone, Jeffrey D; Byrum, C Stephen; Payne, Wyatt G; Smith, David J
2012-01-01
The goal of resident selection is twofold: (1) select candidates who will be successful residents and eventually successful practitioners and (2) avoid selecting candidates who will be unsuccessful residents and/or eventually unsuccessful practitioners. Traditional tools used to select residents have well-known limitations. The Hartman Value Profile (HVP) is a proven adjuvant tool to predicting future performance in candidates for advanced positions in the corporate setting. No literature exists to indicate use of the HVP for resident selection. The HVP evaluates the structure and the dynamics of an individual value system. Given the potential impact, we implemented its use beginning in 2007 as an adjuvant tool to the traditional selection process. Experience gained from incorporating the HVP into the residency selection process suggests that it may add objectivity and refinement in predicting resident performance. Further evaluation is warranted with longer follow-up times.
TRADITIONAL CHINESE HERBAL MEDICINE
ZHU, YP; WOERDENBAG, HJ
1995-01-01
Herbal medicine, acupuncture and moxibustion, and massage and the three major constituent parts of traditional Chinese medicine. Although acupuncture is well known in many Western countries, Chinese herbal medicine, the mos important part of traditional Chinese medicine, is less well known in the
Jorissen, A.J.M.; Hamer, den J.; Leijten, A.J.M.; Salenikovich, A.
2014-01-01
Due to new possibilities traditional timber framing has become increasingly popular since the beginning of the 21e century. Although traditional timber framing has been used for centuries, the expected mechanical behaviour is not dealt with in great detail in building codes, guidelines or text
Political Budget Cycle: Mexican Town Halls Case
Directory of Open Access Journals (Sweden)
Edgar Alfredo Nande Vazque
2016-09-01
Full Text Available In the current economic context, one of the issues of concern is the growth of public spending of municipalities of Mexico and thus increasing public debt. This combines the traditional interest that literature has been devoted to the relationship between economics and politics from the perspective of Political Budget Cycle. The aim of this paper is to analyze the effect of elections in public expenditure management. To this end, a system based on the Generalized Method of Moments (GMM, which uses instrumental variables based on delays and differences of all variables in the model estimator was used. Our findings indicate that there is an expansion of total expenditure, spending on public works and infrastructure and current expenditure contracted work, indicating the preference of politicians for using investment spending to influence voter behavior. The work also notes that citizens value the policies of public expenditure management when making their voting decisions.
A conformal field theory description of fractional quantum Hall states
Ardonne, E.
2002-01-01
In this thesis, we give a description of fractional quantum Hall states in terms of conformal field theory (CFT). As was known for a long time, the Laughlin states could be written in terms of correlators of chiral vertex operators of a c=1 CFT. It was shown by G. Moore and N. Read that more general
The Hall-induced stability of gravitating fluids
Karmakar, P. K.; Goutam, H. P.
2018-05-01
We analyze the stability behavior of low-density partially ionized self-gravitating magnetized unbounded dusty plasma fluid in the presence of the Hall diffusion effects (HDEs) in the non-ideal magnetohydrodynamic (MHD) equilibrium framework. The effects of inhomogeneous self-gravity are methodically included in the basic model tapestry. Application of the Fourier plane-wave perturbative treatment decouples the structuration representative parameters into a linear generalized dispersion relation (sextic) in a judicious mean-fluid approximation. The dispersion analysis shows that the normal mode, termed as the gravito-magneto-acoustic (GMA) mode, is drastically modified due to the HDEs. This mode is highly dispersive, and driven unstable by the Hall current resulting from the symmetry-breaking of electrons and ions relative to the magnetic field. The mode feature, which is derived from a modified induction with the positive Hall, is against the ideal MHD. It is further demonstrated that the HDEs play stabilizing roles by supporting the cloud against gravitational collapse. Provided that the HDEs are concurrently switched off, the collapse occurs on the global spatial scale due to enhanced inward accretion of the gravitating dust constituents. It is seen explicitly that the enhanced dust-charge leads to stabilizing effects. Besides, the Hall-induced fluctuations, as propagatory wave modes, exhibit both normal and anomalous dispersions. The reliability checkup of the entailed results as diverse corollaries and special cases are illustratively discussed in the panoptic light of the earlier paradigmatic predictions available in the literature.
Numerical simulation of SMART-1 Hall-thruster plasma interactions
Tajmar, Martin; Sedmik, René; Scharlemann, Carsten
2009-01-01
SMART-1 has been the first European mission using a Hall thruster to reach the moon. An onboard plasma diagnostic package allowed a detailed characterization of the thruster exhaust plasma and its interactions with the spacecraft. Analysis of in-flight data revealed, amongst others, an unpredicted
Imaging of Coulomb-Driven Quantum Hall Edge States
Lai, Keji; Kundhikanjana, Worasom; Kelly, Michael A.; Shen, Zhi-Xun; Shabani, Javad; Shayegan, Mansour
2011-01-01
The edges of a two-dimensional electron gas (2DEG) in the quantum Hall effect (QHE) regime are divided into alternating metallic and insulating strips, with their widths determined by the energy gaps of the QHE states and the electrostatic Coulomb
Quantum energy teleportation in a quantum Hall system
Energy Technology Data Exchange (ETDEWEB)
Yusa, Go; Izumida, Wataru; Hotta, Masahiro [Department of Physics, Tohoku University, Sendai 980-8578 (Japan)
2011-09-15
We propose an experimental method for a quantum protocol termed quantum energy teleportation (QET), which allows energy transportation to a remote location without physical carriers. Using a quantum Hall system as a realistic model, we discuss the physical significance of QET and estimate the order of energy gain using reasonable experimental parameters.
Interaction Induced Quantum Valley Hall Effect in Graphene
Directory of Open Access Journals (Sweden)
E. C. Marino
2015-03-01
Full Text Available We use pseudo-quantum electrodynamics in order to describe the full electromagnetic interaction of the p electrons in graphene in a consistent 2D formulation. We first consider the effect of this interaction in the vacuum polarization tensor or, equivalently, in the current correlator. This allows us to obtain the T→0 conductivity after a smooth zero-frequency limit is taken in Kubo’s formula. Thereby, we obtain the usual expression for the minimal conductivity plus corrections due to the interaction that bring it closer to the experimental value. We then predict the onset of an interaction-driven spontaneous quantum valley Hall effect below an activation temperature of the order of 2 K. The transverse (Hall valley conductivity is evaluated exactly and shown to coincide with the one in the usual quantum Hall effect. Finally, by considering the effects of pseudo-quantum electrodynamics, we show that the electron self-energy is such that a set of P- and T-symmetric gapped electron energy eigenstates are dynamically generated, in association with the quantum valley Hall effect.
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...
Magnetic microbead detection using the planar Hall effect
International Nuclear Information System (INIS)
Ejsing, Louise; Hansen, Mikkel F.; Menon, Aric K.; Ferreira, Hugo A.; Graham, Daniel L.; Freitas, Paulo P.
2005-01-01
Magnetic sensors based on the planar Hall effect of exchanged-biased permalloy have been fabricated and characterized. It is demonstrated that the sensors are feasible for detecting just a few commercial 2.0 μm magnetic beads commonly used for bioseparation (Micromer-M, Micromod, Germany) and that the sensor sense current is sufficient to generate a signal from the beads
Active Learning with Monty Hall in a Game Theory Class
Brokaw, Alan J.; Merz, Thomas E.
2004-01-01
The authors describe a game that students can play on the first day of a game theory class. The game introduces the 4 essential elements of any game and is designed so that its sequel, also played on the first day of class, has students playing the well-known Monty Hall game, which raises the question: Should you switch doors? By implementing a…
Particle-in-cell simulations of Hall plasma thrusters
Miranda, Rodrigo; Ferreira, Jose Leonardo; Martins, Alexandre
2016-07-01
Hall plasma thrusters can be modelled using particle-in-cell (PIC) simulations. In these simulations, the plasma is described by a set of equations which represent a coupled system of charged particles and electromagnetic fields. The fields are computed using a spatial grid (i.e., a discretization in space), whereas the particles can move continuously in space. Briefly, the particle and fields dynamics are computed as follows. First, forces due to electric and magnetic fields are employed to calculate the velocities and positions of particles. Next, the velocities and positions of particles are used to compute the charge and current densities at discrete positions in space. Finally, these densities are used to solve the electromagnetic field equations in the grid, which are interpolated at the position of the particles to obtain the acting forces, and restart this cycle. We will present numerical simulations using software for PIC simulations to study turbulence, wave and instabilities that arise in Hall plasma thrusters. We have sucessfully reproduced a numerical simulation of a SPT-100 Hall thruster using a two-dimensional (2D) model. In addition, we are developing a 2D model of a cylindrical Hall thruster. The results of these simulations will contribute to improve the performance of plasma thrusters to be used in Cubesats satellites currenty in development at the Plasma Laboratory at University of Brasília.
Hall kirjandus võrgustunud maailmas / Anneli Kuiv
Kuiv, Anneli
2003-01-01
1997. aasta määratluse kohaselt on hall kirjandus "kirjandus, mida toodetakse kõikidel tasanditel valitsus- ja teadusasutuste, äri- ja tootmisringkondade poolt nii trükituna kui ka elektroonselt, kuid mis ei ole kirjastustööstuse kontrolli all"
Hall effects on MHD flow past an accelerated plate
International Nuclear Information System (INIS)
Soundalgekar, V.M.; Ravi, S.; Hiremath, S.B.
1980-01-01
An exact solution of the MHD flow of an incompressible, electrically conducting, viscous fluid past a uniformly accelerated plate is presented. The velocity profiles are shown graphically and the numerical values of axial and transverse components of skin friction are tabulated. At high values of the Hall parameter, ωtau, the velocity is found to be oscillatory near the plate. (author)
new concepts of a modified hall - petch type relationship
African Journals Online (AJOL)
NIJOTECH
Abstract. A modified form of the Hall - Perch equation, where the average grain diameter is replaced by the surface to volume ratio of internal boundaries (Sv), is considered. Working with this model, a flow stress – Sv relationship dominated by geometrically necessary dislocations (GNDs) is derived for the low strain region.
Effect of Hall Current and Finite Larmor Radius Corrections on ...
Indian Academy of Sciences (India)
Home; Journals; Journal of Astrophysics and Astronomy; Volume 37; Issue 3. Effect of Hall Current and Finite Larmor Radius Corrections on Thermal Instability of Radiative Plasma for Star Formation in Interstellar Medium (ISM). Sachin Kaothekar. Research Article Volume 37 Issue 3 September 2016 Article ID 23 ...
Energy efficient heating and ventilation of large halls
Hojer, Ondrej; Kabele, Karel; Kotrbaty, Miroslav; Sommer, Klaus; Petras, Dusan
2011-01-01
This guidebook is focused on modern methods for design, control and operation of energy efficient heating systems in large spaces and industrial halls. The book deals with thermal comfort, light and dark gas radiant heaters, panel radiant heating, floor heating and industrial air heating systems. Various heating systems are illustrated with case studies. Design principles, methods and modeling tools are presented for various systems.
Composite fermions a unified view of the quantum Hall regime
1998-01-01
One of the most exciting recent developments to have emerged from the quantum Hall effect is the subject of composite fermions. This important volume gives a self-contained, comprehensive description of the subject, including fundamentals, more advanced theoretical work, and results from experimental observations of composite fermions.
Virginia Tech's College Of Natural Resources Dedicates Cheatham Hall Expansion
Davis, Lynn
2003-01-01
Thanks to funding by private donors, Alyce Cheatham and her family of Portland, Oregon, Virginia Tech's College of Natural Resources will dedicate a much-needed, three-story addition to its current Cheatham Hall on Wednesday, March 19, at 2:30 p.m.
Tondiraba jäähall = Tondiraba ice arena
2015-01-01
Tondiraba jäähall Tallinnas Varraku tänav 14, valminud 2014. Arhitektid Ott Kadarik, Mihkel Tüür, Kadri Tamme (Kadarik Tüür Arhitektid OÜ), insener Paavo Pikand. Eesti Kultuurkapitali Arhitektuuri sihtkapitali aastapreemia 2014
Field theory of anyons and the fractional quantum Hall effect
International Nuclear Information System (INIS)
Viefers, S.F.
1997-11-01
The thesis is devoted to a theoretical study of anyons, i.e. particles with fractional statistics moving in two space dimensions, and the quantum Hall effect. The latter constitutes the only known experimental realization of anyons in that the quasiparticle excitations in the fractional quantum Hall system are believed to obey fractional statistics. First, the properties of ideal quantum gases in two dimensions and in particular the equation of state of the free anyons gas are discussed. Then, a field theory formulation of anyons in a strong magnetic field is presented and later extended to a system with several species of anyons. The relation of this model to fractional exclusion statistics, i.e. intermediate statistics introduced by a generalization of the Pauli principle, and to the low-energy excitations at the edge of the quantum Hall system is discussed. Finally, the Chern-Simons-Landau-Ginzburg theory of the fractional quantum Hall effect is studied, mainly focusing on edge effects; both the ground state and the low-energy edge excitations are examined in the simple one-component model and in an extended model which includes spin effects
Magnus force on quantum Hall skyrmions and vortices
International Nuclear Information System (INIS)
Dhar, S.; Basu, B.; Bandyopadhyay, P.
2003-01-01
We have discussed here the Magnus force acting on the vortices and skyrmions in the quantum Hall systems. We have found that it is generated by the chirality of the system which is associated with the Berry phase and is same for both the cases
Single particle detection: Phase control in submicron Hall sensors
International Nuclear Information System (INIS)
Di Michele, Lorenzo; Shelly, Connor; Gallop, John; Kazakova, Olga
2010-01-01
We present a phase-sensitive ac-dc Hall magnetometry method which allows a clear and reliable separation of real and parasitic magnetic signals of a very small magnitude. High-sensitivity semiconductor-based Hall crosses are generally accepted as a preferential solution for non-invasive detection of superparamagnetic nanobeads used in molecular biology, nanomedicine, and nanochemistry. However, detection of such small beads is often hindered by inductive pick-up and other spurious signals. The present work demonstrates an unambiguous experimental route for detection of small magnetic moments and provides a simple theoretical background for it. The reliability of the method has been tested for a variety of InSb Hall sensors in the range 600 nm-5 μm. Complete characterization of empty devices, involving Hall coefficients and noise measurements, has been performed and detection of a single FePt bead with diameter of 140 nm and magnetic moment of μ≅10 8 μ B has been achieved with a 600 nm-wide sensor.
Low-frequency noise in planar Hall effect bridge sensors
DEFF Research Database (Denmark)
Persson, Anders; Bejhedb, R.S.; Bejhed, R.S.
2011-01-01
The low-frequency characteristics of planar Hall effect bridge sensors are investigated as function of the sensor bias current and the applied magnetic field. The noise spectra reveal a Johnson-like spectrum at high frequencies, and a 1/f-like excess noise spectrum at lower frequencies, with a kn...
Quantum Hall Effect: proposed multi-electron tunneling experiment
International Nuclear Information System (INIS)
Kostadinov, I.Z.
1985-11-01
Here we propose a tunneling experiment for the fractional and Integral Quantum Hall Effect. It may demonstrate multi-electron tunneling and may provide information about the nature of the macroscopic quantum states of 2D electronic liquid or solid. (author)
Observation of the fractional quantum Hall effect in graphene.
Bolotin, Kirill I; Ghahari, Fereshte; Shulman, Michael D; Stormer, Horst L; Kim, Philip
2009-11-12
When electrons are confined in two dimensions and subject to strong magnetic fields, the Coulomb interactions between them can become very strong, leading to the formation of correlated states of matter, such as the fractional quantum Hall liquid. In this strong quantum regime, electrons and magnetic flux quanta bind to form complex composite quasiparticles with fractional electronic charge; these are manifest in transport measurements of the Hall conductivity as rational fractions of the elementary conductance quantum. The experimental discovery of an anomalous integer quantum Hall effect in graphene has enabled the study of a correlated two-dimensional electronic system, in which the interacting electrons behave like massless chiral fermions. However, owing to the prevailing disorder, graphene has so far exhibited only weak signatures of correlated electron phenomena, despite intense experimental and theoretical efforts. Here we report the observation of the fractional quantum Hall effect in ultraclean, suspended graphene. In addition, we show that at low carrier density graphene becomes an insulator with a magnetic-field-tunable energy gap. These newly discovered quantum states offer the opportunity to study correlated Dirac fermions in graphene in the presence of large magnetic fields.
Mechanism of plateau formation in the fractional quantum Hall effect
International Nuclear Information System (INIS)
Bruus, H.; Hansen, O.P.; Hansen, E.B.
1988-01-01
Laughlin's fractionally charged quasi-holes and quasi-electrons are assumed to be pinned, and to be subject to a force j vectorxΦ 0 vector from the transport current. A force balance argument then explains the existence of Hall plateaus. (orig.)
Planar Hall effect sensor for magnetic micro- and nanobead detection
DEFF Research Database (Denmark)
Ejsing, Louise Wellendorph; Hansen, Mikkel Fougt; Menon, Aric Kumaran
2004-01-01
Magnetic bead sensors based on the planar Hall effect in thin films of exchange-biased permalloy have been fabricated and characterized. Typical sensitivities are 3 muV/Oe mA. The sensor response to an applied magnetic field has been measured without and with coatings of commercially available 2 ...
Mini array of quantum Hall devices based on epitaxial graphene
International Nuclear Information System (INIS)
Novikov, S.; Lebedeva, N.; Hämäläinen, J.; Iisakka, I.; Immonen, P.; Manninen, A. J.; Satrapinski, A.
2016-01-01
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 R H,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×R H,2 = 2 h/e 2 was smaller than the relative standard uncertainty of the measurement (<1 × 10 −7 ) limited by the used resistance bridge.
Hall Thruster Thermal Modeling and Test Data Correlation
Myers, James; Kamhawi, Hani; Yim, John; Clayman, Lauren
2016-01-01
The life of Hall Effect thrusters are primarily limited by plasma erosion and thermal related failures. NASA Glenn Research Center (GRC) in cooperation with the Jet Propulsion Laboratory (JPL) have recently completed development of a Hall thruster with specific emphasis to mitigate these limitations. Extending the operational life of Hall thursters makes them more suitable for some of NASA's longer duration interplanetary missions. This paper documents the thermal model development, refinement and correlation of results with thruster test data. Correlation was achieved by minimizing uncertainties in model input and recognizing the relevant parameters for effective model tuning. Throughout the thruster design phase the model was used to evaluate design options and systematically reduce component temperatures. Hall thrusters are inherently complex assemblies of high temperature components relying on internal conduction and external radiation for heat dispersion and rejection. System solutions are necessary in most cases to fully assess the benefits and/or consequences of any potential design change. Thermal model correlation is critical since thruster operational parameters can push some components/materials beyond their temperature limits. This thruster incorporates a state-of-the-art magnetic shielding system to reduce plasma erosion and to a lesser extend power/heat deposition. Additionally a comprehensive thermal design strategy was employed to reduce temperatures of critical thruster components (primarily the magnet coils and the discharge channel). Long term wear testing is currently underway to assess the effectiveness of these systems and consequently thruster longevity.
NASA HERMeS Hall Thruster Electrical Configuration Characterization
Peterson, Peter; Kamhawi, Hani; Huang, Wensheng; Yim, John; Herman, Daniel; Williams, George; Gilland, James; Hofer, Richard
2016-01-01
NASAs 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 presentation will cover the electrical configuration testing of the TDU-1 HERMeS Hall thruster in NASA Glenn Research Centers Vacuum Facility 5. The three electrical configurations examined are the thruster body tied to facility ground, thruster floating, and finally the thruster body electrically tied to cathode common. The TDU-1 HERMeS was configured with two different exit plane boundary conditions, dielectric and conducting, to examine the influence on the electrical configuration characterization.
An evaluation of krypton propellant in Hall thrusters
Linnell, Jesse Allen
Due to its high specific impulse and low price, krypton has long sparked interest as an alternate Hall thruster propellant. Unfortunately at the moment, krypton's relatively poor performance precludes it as a legitimate option. This thesis presents a detailed investigation into krypton operation in Hall thrusters. These findings suggest that the performance gap can be decreased to 4% and krypton can finally become a realistic propellant option. Although krypton has demonstrated superior specific impulse, the xenon-krypton absolute efficiency gap ranges between 2 and 15%. A phenomenological performance model indicates that the main contributors to the efficiency gap are propellant utilization and beam divergence. Propellant utilization and beam divergence have relative efficiency deficits of 5 and 8%, respectively. A detailed characterization of internal phenomena is conducted to better understand the xenon-krypton efficiency gap. Krypton's large beam divergence is found to be related to a defocusing equipotential structure and a weaker magnetic field topology. Ionization processes are shown to be linked to the Hall current, the magnetic mirror topology, and the perpendicular gradient of the magnetic field. Several thruster design and operational suggestions are made to optimize krypton efficiency. Krypton performance is optimized for discharge voltages above 500 V and flow rates corresponding to an a greater than 0.015 mg/(mm-s), where alpha is a function of flow rate and discharge channel dimensions (alpha = m˙alphab/Ach). Performance can be further improved by increasing channel length or decreasing channel width for a given flow rate. Also, several magnetic field design suggestions are made to enhance ionization and beam focusing. Several findings are presented that improve the understanding of general Hall thruster physics. Excellent agreement is shown between equipotential lines and magnetic field lines. The trim coil is shown to enhance beam focusing
Quantum Hall conductivity in a Landau type model with a realistic geometry
International Nuclear Information System (INIS)
Chandelier, F.; Georgelin, Y.; Masson, T.; Wallet, J.-C.
2003-01-01
In this paper, we revisit some quantum mechanical aspects related to the quantum Hall effect. We consider a Landau type model, paying a special attention to the experimental and geometrical features of quantum Hall experiments. The resulting formalism is then used to compute explicitly the Hall conductivity from a Kubo formula
Current Percolation in Medium with Boundaries under Quantum Hall Effect Conditions
Directory of Open Access Journals (Sweden)
M. U. Malakeeva
2012-01-01
Full Text Available The current percolation has been considered in the medium with boundaries under quantum Hall effect conditions. It has been shown that in that case the effective Hall conductivity has a nonzero value due to percolation of the Hall current through the finite number of singular points (in our model these are corners at the phase joints.
Lawful Permanent Residents - Annual Report
Department of Homeland Security — A lawful permanent resident (LPR) or 'green card' recipient is defined by immigration law as a person who has been granted lawful permanent residence in the United...
Experimental and theoretical studies of cylindrical Hall thrusters
International Nuclear Information System (INIS)
Smirnov, Artem; Raitses, Yegeny; Fisch, Nathaniel J.
2007-01-01
The Hall thruster is a mature electric propulsion device that holds considerable promise in terms of the propellant saving potential. The annular design of the conventional Hall thruster, however, does not naturally scale to low power. The efficiency tends to be lower and the lifetime issues are more aggravated. Cylindrical geometry Hall thrusters have lower surface-to-volume ratio than conventional thrusters and, thus, seem to be more promising for scaling down. The cylindrical Hall thruster (CHT) is fundamentally different from the conventional design in the way the electrons are confined and the ion space charge is neutralized. The performances of both the large (9-cm channel diameter, 600-1000 W) and miniaturized (2.6-cm channel diameter, 50-300 W) CHTs are comparable with those of the state-of-the-art conventional (annular) design Hall thrusters of similar sizes. A comprehensive experimental and theoretical study of the CHT physics has been conducted, addressing the questions of electron cross-field transport, propellant ionization, plasma-wall interaction, and formation of the electron distribution function. Probe measurements in the harsh plasma environment of the microthruster were performed. Several interesting effects, such as the unusually high ionization efficiency and enhanced electron transport, were observed. Kinetic simulations suggest the existence of the strong fluctuation-enhanced electron diffusion and predict the non-Maxwellian shape of the electron distribution function. Through the acquired understanding of the new physics, ways for further optimization of this means for low-power space propulsion are suggested. Substantial flexibility in the magnetic field configuration of the CHT is the key tool in achieving the high-efficiency operation
Traditional medicine and genomics
Directory of Open Access Journals (Sweden)
Kalpana Joshi
2010-01-01
Full Text Available ′Omics′ developments in the form of genomics, proteomics and metabolomics have increased the impetus of traditional medicine research. Studies exploring the genomic, proteomic and metabolomic basis of human constitutional types based on Ayurveda and other systems of oriental medicine are becoming popular. Such studies remain important to developing better understanding of human variations and individual differences. Countries like India, Korea, China and Japan are investing in research on evidence-based traditional medicines and scientific validation of fundamental principles. This review provides an account of studies addressing relationships between traditional medicine and genomics.
Traditional medicine and genomics.
Joshi, Kalpana; Ghodke, Yogita; Shintre, Pooja
2010-01-01
'Omics' developments in the form of genomics, proteomics and metabolomics have increased the impetus of traditional medicine research. Studies exploring the genomic, proteomic and metabolomic basis of human constitutional types based on Ayurveda and other systems of oriental medicine are becoming popular. Such studies remain important to developing better understanding of human variations and individual differences. Countries like India, Korea, China and Japan are investing in research on evidence-based traditional medicines and scientific validation of fundamental principles. This review provides an account of studies addressing relationships between traditional medicine and genomics.
Pediatric resident perceptions of shift work in ward rotations.
Nomura, Osamu; Mishina, Hiroki; Jasti, Harish; Sakai, Hirokazu; Ishiguro, Akira
2017-10-01
Although the long working hours of physicians are considered to be a social issue, no effective policies such as duty hour regulations have so far been proposed in Japan. We implemented an overnight call shift (OCS) system for ward rotations to improve the working environment for residents in a pediatric residency program. We later conducted a cross-sectional questionnaire asking the residents to compare this system with the traditional overnight call system. Forty-one pediatric residents participated in this survey. The residents felt that the quality of patient care improved (80.4% agreed). Most felt that there was less emphasis on education (26.8%) and more emphasis on service (31.7%). Overall, the residents reported that the OCS was beneficial (90.2%). In conclusion, the pediatric residents considered the OCS system during ward rotations as beneficial. Alternative solutions are vital to balance improvements in resident work conditions with the requirement for a high quality of education. © 2017 Japan Pediatric Society.
Impact of Residency Training Redesign on Residents' Clinical Knowledge.
Waller, Elaine; Eiff, M Patrice; Dexter, Eve; Rinaldo, Jason C B; Marino, Miguel; Garvin, Roger; Douglass, Alan B; Phillips, Robert; Green, Larry A; Carney, Patricia A
2017-10-01
The In-training Examination (ITE) is a frequently used method to evaluate family medicine residents' clinical knowledge. We compared family medicine ITE scores among residents who trained in the 14 programs that participated in the Preparing the Personal Physician for Practice (P4) Project to national averages over time, and according to educational innovations. The ITE scores of 802 consenting P4 residents who trained in 2007 through 2011 were obtained from the American Board of Family Medicine. The primary analysis involved comparing scores within each academic year (2007 through 2011), according to program year (PGY) for P4 residents to all residents nationally. A secondary analysis compared ITE scores among residents in programs that experimented with length of training and compared scores among residents in programs that offered individualized education options with those that did not. Release of ITE scores was consented to by 95.5% of residents for this study. Scores of P4 residents were higher compared to national scores in each year. For example, in 2011, the mean P4 score for PGY1 was 401.2, compared to the national average of 386. For PGY2, the mean P4 score was 443.1, compared to the national average of 427, and for PGY3, the mean P4 score was 477.0, compared to the national PGY3 score of 456. Scores of residents in programs that experimented with length of training were similar to those in programs that did not. Scores were also similar between residents in programs with and without individualized education options. Family medicine residency programs undergoing substantial educational changes, including experiments in length of training and individualized education, did not appear to experience a negative effect on resident's clinical knowledge, as measured by ITE scores. Further research is needed to study the effect of a wide range of residency training innovations on ITE scores over time.
Gonzaga, Rosemary; Matzinger, Polly; Perez-Diez, Ainhoa
2011-01-01
Here we describe a new population of NK cells that reside in the normal, un-inflamed peritoneal cavity. Phenotypically, they share some similarities with the small population of CD49b negative, CD27 positive immature splenic NK cells, and liver NK cells but differ in their expression of CD62L, TRAIL and EOMES. Functionally, the peritoneal NK cells resemble the immature splenic NK cells in their production of IFN-γ, GM-CSF and TNF-α and in the killing of YAC-1 target cells. We also found that the peritoneum induces different behavior in mature and immature splenic NK cells. When transferred intravenously into RAGγcKO mice, both populations undergo homeostatic proliferation in the spleen, but only the immature splenic NK cells, are able to reach the peritoneum. When transferred directly into the peritoneum, the mature NK cells survive but do not divide, while the immature NK cells proliferate profusely. These data suggest that the peritoneum is not only home to a new subset of tissue resident NK cells but that it differentially regulates the migration and homeostatic proliferation of immature versus mature NK cells. PMID:22079985
SPATIAL ANALYSIS OF RESIDENTS' FEAR AND FEELING OF ...
African Journals Online (AJOL)
Osondu
Abstract. This study examined spatial pattern of crime and residents' fear and feeling of insecurity in Ile-Ife,. Nigeria. To obtain the primary data, Ile-Ife was stratified into four residential zones namely traditional town centre, middle income, high income and post-crisis residential areas. Sample was selected using systematic ...
A Monolithic CMOS Magnetic Hall Sensor with High Sensitivity and Linearity Characteristics.
Huang, Haiyun; Wang, Dejun; Xu, Yue
2015-10-27
This paper presents a fully integrated linear Hall sensor by means of 0.8 μm high voltage complementary metal-oxide semiconductor (CMOS) technology. This monolithic Hall sensor chip features a highly sensitive horizontal switched Hall plate and an efficient signal conditioner using dynamic offset cancellation technique. An improved cross-like Hall plate achieves high magnetic sensitivity and low offset. A new spinning current modulator stabilizes the quiescent output voltage and improves the reliability of the signal conditioner. The tested results show that at the 5 V supply voltage, the maximum Hall output voltage of the monolithic Hall sensor microsystem, is up to ±2.1 V and the linearity of Hall output voltage is higher than 99% in the magnetic flux density range from ±5 mT to ±175 mT. The output equivalent residual offset is 0.48 mT and the static power consumption is 20 mW.
Kuek, K; Liow, T S
1985-01-01
The Chinese traditional medical system and pharmacology have a 1000-year history, and practitioners of Chinese traditional medicine play an important role in providing health care and family planning services in China. Vast numbers of patients from all walks of life and of all races benefit from Chinese traditional medicine. Although there are no official government records on the activities of practitioners of traditional medicine, the Chinese charitable medical organizations have some data on the nature of available services and their use. In China, in the context of significant government investment in health care facilities throughout the country and the proliferation of private hospitals, specialist centers, and general practitioners providing modern health care, the number of Chinese traditional charity medical aid departments, instead of falling by the wayside, has increased. The Chinese Traditional Medicine and Physician and Medicine Dealers Association of Malaysia was established 27 years ago. There are now officially 719 Chinese physicians and 1869 medical halls and Chinese physician infirmaries in Malaysia. The authors describe the status of Chinese physicians and medical halls in Malaysia, charitable organizations, and applications of Chinese traditional medicine.
KASTAMONU TRADITIONAL WOMEN CLOTHES
Directory of Open Access Journals (Sweden)
E.Elhan ÖZUS
2015-08-01
Full Text Available Clothing is a unique dressing style of a community, a period or a profession. In clothing there is social status and difference principle rather than fashion. In this context, the society created a clothing style in line with its own customs, traditions and social structure. One of the features separating societies from each other and indicating their cultural and social classes is the clothing style. As it is known, traditional Turkish clothes reflecting the characteristics of Turkish society is our most beautiful heritage from past to present. From this heritage there are several examples of women's clothes c arried to present. When these examples are examined, it is possible to see the taste, the way of understanding art, joy and the lifestyle of the history. These garments are also the documents outlining the taste and grace of Turkish people. In the present study, traditional Kastamonu women's clothing, that has an important place in traditional cultural clothes of Anatolia, is investigated . The method of the present research is primarily defined as the examination of the written sources. The study is complet ed with the observations and examinations made in Kastamonu. According to the findings of the study, traditional Kastamonu women's clothing are examined and adapted to todays’ clothing.
Audience noise in concert halls during musical performances
DEFF Research Database (Denmark)
Jeong, Cheol-Ho; Marie, Pierre; Brunskog, Jonas
2012-01-01
functions of the sound pressure levels were obtained in octave bands, which were fitted with three Gaussian distribution curves. The Gaussian distribution curve with the lowest mean value corresponds to a mixture of the technical background noise and audience generated noise, which is named the mixed...... background noise. Finally, the audience noise distribution is extracted by energy subtraction of the technical background noise levels measured in an empty condition from the mixed background noise levels. As a single index, L-90 of the audience noise distribution is named the audience noise level. Empirical...... 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...
Audience noise in concert halls during musical performances
DEFF Research Database (Denmark)
Marie, Pierre; Jeong, Cheol-Ho; Brunskog, Jonas
2012-01-01
functions of the sound pressure levels were obtained in octave bands, which were fitted with three Gaussian distribution curves. The Gaussian distribution curve with the lowest mean value corresponds to a mixture of the technical background noise and audience generated noise, which is named the mixed...... background noise. Finally, the audience noise distribution is extracted by energy subtraction of the technical background noise levels measured in an empty condition from the mixed background noise levels. As a single index, L90 of the audience noise distribution is named the audience noise level. Empirical...... 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....
Precise quantization of anomalous Hall effect near zero magnetic field
Energy Technology Data Exchange (ETDEWEB)
Bestwick, A. J. [Stanford Univ., Stanford, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States); Fox, E. J. [Stanford Univ., Stanford, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States); Kou, Xufeng [Univ. of California, Los Angeles, CA (United States); Pan, Lei [Univ. of California, Los Angeles, CA (United States); Wang, Kang L. [Univ. of California, Los Angeles, CA (United States); Goldhaber-Gordon, D. [Stanford Univ., Stanford, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States)
2015-05-04
In this study, we report a nearly ideal quantum anomalous Hall effect in a three-dimensional topological insulator thin film with ferromagnetic doping. Near zero applied magnetic field we measure exact quantization in the Hall resistance to within a part per 10,000 and a longitudinal resistivity under 1 Ω per square, with chiral edge transport explicitly confirmed by nonlocal measurements. Deviations from this behavior are found to be caused by thermally activated carriers, as indicated by an Arrhenius law temperature dependence. Using the deviations as a thermometer, we demonstrate an unexpected magnetocaloric effect and use it to reach near-perfect quantization by cooling the sample below the dilution refrigerator base temperature in a process approximating adiabatic demagnetization refrigeration.
Modeling of the near field plume of a Hall thruster
International Nuclear Information System (INIS)
Boyd, Iain D.; Yim, John T.
2004-01-01
In this study, a detailed numerical model is developed to simulate the xenon plasma near-field plume from a Hall thruster. The model uses a detailed fluid model to describe the electrons and a particle-based kinetic approach is used to model the heavy xenon ions and atoms. The detailed model is applied to compute the near field plume of a small, 200 W Hall thruster. Results from the detailed model are compared with the standard modeling approach that employs the Boltzmann model. The usefulness of the model detailed is assessed through direct comparisons with a number of different measured data sets. The comparisons illustrate that the detailed model accurately predicts a number of features of the measured data not captured by the simpler Boltzmann approach
Multi-region relaxed Hall magnetohydrodynamics with flow
Energy Technology Data Exchange (ETDEWEB)
Lingam, Manasvi, E-mail: mlingam@princeton.edu [Department of Astrophysical Sciences, Princeton University, Princeton, New Jersey 08544 (United States); Abdelhamid, Hamdi M., E-mail: hamdi@ppl.k.u-tokyo.ac.jp [Graduate School of Frontier Sciences, The University of Tokyo, Kashiwanoha, Kashiwa, Chiba 277-8561 (Japan); Physics Department, Faculty of Science, Mansoura University, Mansoura 35516 (Egypt); Hudson, Stuart R., E-mail: shudson@pppl.gov [Princeton Plasma Physics Laboratory, PO Box 451, Princeton, New Jersey 08543 (United States)
2016-08-15
The recent formulations of multi-region relaxed magnetohydrodynamics (MRxMHD) have generalized the famous Woltjer-Taylor states by incorporating a collection of “ideal barriers” that prevent global relaxation and flow. In this paper, we generalize MRxMHD with flow to include Hall effects, and thereby obtain the partially relaxed counterparts of the famous double Beltrami states as a special subset. The physical and mathematical consequences arising from the introduction of the Hall term are also presented. We demonstrate that our results (in the ideal MHD limit) constitute an important subset of ideal MHD equilibria, and we compare our approach against other variational principles proposed for deriving the partially relaxed states.
Contactless measurement of alternating current conductance in quantum Hall structures
Energy Technology Data Exchange (ETDEWEB)
Drichko, I. L.; Diakonov, A. M.; Malysh, V. A.; Smirnov, I. Yu.; Ilyinskaya, N. D.; Usikova, A. A. [A. F. Ioffe Physical-Technical Institute of the Russian Academy of Sciences, 194021 St. Petersburg (Russian Federation); Galperin, Y. M. [Department of Physics, University of Oslo, P.O. Box 1048 Blindern, 0316 Oslo (Norway); A. F. Ioffe Physical-Technical Institute of the Russian Academy of Sciences, 194021 St. Petersburg (Russian Federation); Kummer, M.; Känel, H. von [Laboratorium für Festkörperphysik ETH Zürich, CH-8093 Zürich (Switzerland)
2014-10-21
We report a procedure to determine the frequency-dependent conductance of quantum Hall structures in a broad frequency domain. The procedure is based on the combination of two known probeless methods—acoustic spectroscopy and microwave spectroscopy. By using the acoustic spectroscopy, we study the low-frequency attenuation and phase shift of a surface acoustic wave in a piezoelectric crystal in the vicinity of the electron (hole) layer. The electronic contribution is resolved using its dependence on a transverse magnetic field. At high frequencies, we study the attenuation of an electromagnetic wave in a coplanar waveguide. To quantitatively calibrate these data, we use the fact that in the quantum-Hall-effect regime the conductance at the maxima of its magnetic field dependence is determined by extended states. Therefore, it should be frequency independent in a broad frequency domain. The procedure is verified by studies of a well-characterized p-SiGe/Ge/SiGe heterostructure.
Tunneling Spectroscopy of Quantum Hall States in Bilayer Graphene
Wang, Ke; Harzheim, Achim; Watanabe, Kenji; Taniguchi, Takashi; Kim, Philip
In the quantum Hall (QH) regime, ballistic conducting paths along the physical edges of a sample appear, leading to quantized Hall conductance and vanishing longitudinal magnetoconductance. These QH edge states are often described as ballistic compressible strips separated by insulating incompressible strips, the spatial profiles of which can be crucial in understanding the stability and emergence of interaction driven QH states. In this work, we present tunneling transport between two QH edge states in bilayer graphene. Employing locally gated device structure, we guide and control the separation between the QH edge states in bilayer graphene. Using resonant Landau level tunneling as a spectroscopy tool, we measure the energy gap in bilayer graphene as a function of displacement field and probe the emergence and evolution of incompressible strips.
Sensitivity of resistive and Hall measurements to local inhomogeneities
DEFF Research Database (Denmark)
Koon, Daniel W.; Wang, Fei; Petersen, Dirch Hjorth
2014-01-01
We derive exact, analytic expressions for the sensitivity of sheet resistance and Hall sheet resistance measurements to local inhomogeneities for the cases of nonzero magnetic fields, strong perturbations, and perturbations over a finite area, extending our earlier results on weak perturbations. ...... simulations on both a linear four-point probe array on a large circular disc and a van der Pauw square geometry. Furthermore, the results also agree well with Náhlík et al. published experimental results for physical holes in a circular copper foil disc.......We derive exact, analytic expressions for the sensitivity of sheet resistance and Hall sheet resistance measurements to local inhomogeneities for the cases of nonzero magnetic fields, strong perturbations, and perturbations over a finite area, extending our earlier results on weak perturbations. We...
Fast micro Hall effect measurements on small pads
DEFF Research Database (Denmark)
Østerberg, Frederik Westergaard; Petersen, Dirch Hjorth; Nielsen, Peter F.
2011-01-01
Sheet resistance, carrier mobility, and sheet carrier density are important parameters in semiconductor production, and it is therefore important to be able to rapidly and accurately measure these parameters even on small samples or pads. The interpretation of four-point probe measurements on small...... pads is non-trivial. In this paper we discuss how conformal mapping can be used to evaluate theoretically expected measurement values on small pads. Theoretical values calculated from analytical mappings of simple geometries are compared to the values found from the numerical conformal mapping...... of a square onto the infinite half-plane, where well-established solutions are known. Hall effect measurements are performed to show, experimentally, that it is possible to measure Hall mobility in less than one minute on squares as small as 7070 lm2 with a deviation of 66.5% on a 1r level from accurate...
Anomalous Hall effect and Nernst effect in itinerant ferromagnets
International Nuclear Information System (INIS)
Asamitsu, A.; Miyasato, T.; Abe, N.; Fujii, T.; Onose, Y.; Onoda, S.; Nagaosa, N.; Tokura, Y.
2007-01-01
Anomalous Hall effect (AHE) and anomalous Nernst effect (ANE) in many ferromagnetic metals including pure metals, oxides, and calcogenides, are studied to obtain unified understandings of their origins. We show the universal behavior of anomalous Hall conductivity σ xy as a function of longitudinal conductivity σ xx over six orders of magnitude, which is well reproduced by rigorous unified theory assuming both intrinsic and extrinsic contributions to the AHE. ANE is closely related with AHE and gives us further information about the electronic state in the ground state of ferromagnets. The temperature dependence of transverse Peltier coefficient α xy shows almost similar behavior among various ferromagnets and this behavior is expected from a conventional Boltzmann transport theory
Quantum Hall effect in epitaxial graphene with permanent magnets.
Parmentier, F D; Cazimajou, T; Sekine, Y; Hibino, H; Irie, H; Glattli, D C; Kumada, N; Roulleau, P
2016-12-06
We have observed the well-kown quantum Hall effect (QHE) in epitaxial graphene grown on silicon carbide (SiC) by using, for the first time, only commercial NdFeB permanent magnets at low temperature. The relatively large and homogeneous magnetic field generated by the magnets, together with the high quality of the epitaxial graphene films, enables the formation of well-developed quantum Hall states at Landau level filling factors v = ±2, commonly observed with superconducting electro-magnets. Furthermore, the chirality of the QHE edge channels can be changed by a top gate. These results demonstrate that basic QHE physics are experimentally accessible in graphene for a fraction of the price of conventional setups using superconducting magnets, which greatly increases the potential of the QHE in graphene for research and applications.
Quantum Hall Valley Nematics: From Field Theories to Microscopic Models
Parameswaran, Siddharth
The interplay between quantum Hall ordering and spontaneously broken ``internal'' symmetries in two-dimensional electron systems with spin or pseudospin degrees of freedom gives rise to a variety of interesting phenomena, including novel phases, phase transitions, and topological excitations. I will discuss a theory of broken-symmetry quantum Hall states, applicable to a class of multivalley systems, where the symmetry at issue is a point-group element that combines a spatial rotation with a permutation of valley indices. I will explore its ramifications for the phase diagram of a variety of experimental systems, such as AlAs and Si quantum wells and the surface states of bismuth. I will also discuss unconventional transport phenomena in these phases in the presence of quenched randomness, and the possible mechanisms of selection between degenerate broken-symmetry phases in clean systems. I acknowledge support from NSF DMR-1455366.
Matrix effective theories of the fractional quantum Hall effect
International Nuclear Information System (INIS)
Cappelli, Andrea; Rodriguez, Ivan D
2009-01-01
The present understanding of nonperturbative ground states in the fractional quantum Hall effect is based on effective theories of the Jain 'composite fermion' excitations. We review the approach based on matrix variables, i.e. D0 branes, originally introduced by Susskind and Polychronakos. We show that the Maxwell-Chern-Simons matrix gauge theory provides a matrix generalization of the quantum Hall effect, where the composite-fermion construction naturally follows from gauge invariance. The matrix ground states obtained by suitable projections of higher Landau levels are found to be in one-to-one correspondence with the Laughlin and Jain hierarchical states. The matrix theory possesses a physical limit for commuting matrices that could be reachable while staying in the same phase.
Intermittency in Hall-magnetohydrodynamics with a strong guide field
International Nuclear Information System (INIS)
Rodriguez Imazio, P.; Martin, L. N.; Dmitruk, P.; Mininni, P. D.
2013-01-01
We present a detailed study of intermittency in the velocity and magnetic field fluctuations of compressible Hall-magnetohydrodynamic turbulence with an external guide field. To solve the equations numerically, a reduced model valid when a strong guide field is present is used. Different values for the ion skin depth are considered in the simulations. The resulting data are analyzed computing field increments in several directions perpendicular to the guide field, and building structure functions and probability density functions. In the magnetohydrodynamic limit, we recover the usual results with the magnetic field being more intermittent than the velocity field. In the presence of the Hall effect, field fluctuations at scales smaller than the ion skin depth show a substantial decrease in the level of intermittency, with close to monofractal scaling
Quasiparticle Aggregation in the Fractional Quantum Hall Effect
Laughlin, R. B.
1984-10-10
Quasiparticles in the Fractional Quantum Hall Effect behave qualitatively like electrons confined to the lowest landau level, and can do everything electrons can do, including condense into second generation Fractional Quantum Hall ground states. I review in this paper the reasoning leading to variational wavefunctions for ground state and quasiparticles in the 1/3 effect. I then show how two-quasiparticle eigenstates are uniquely determined from symmetry, and how this leads in a natural way to variational wavefunctions for composite states which have the correct densities (2/5, 2/7, ...). I show in the process that the boson, anyon and fermion representations for the quasiparticles used by Haldane, Halperin, and me are all equivalent. I demonstrate a simple way to derive Halperin`s multiple-valued quasiparticle wavefunction from the correct single-valued electron wavefunction. (auth)
Admittance measurements in the quantum Hall effect regime
Energy Technology Data Exchange (ETDEWEB)
Hernández, C., E-mail: carlos.hernandezr@unimilitar.edu.co [Departamento de Física, Universidad Militar Nueva Granada, Carrera 11 # 101-80, Bogotá D.C. (Colombia); Laboratorio de Magnetismo, Departamento de Física, Universidad de los Andes, A.A. 4976, Bogotá D.C. (Colombia); Consejo, C.; Chaubet, C. [Laboratoire Charles Coulomb L2C, Université Montpellier II, Pl. E. Bataillon, 34095 Montpellier Cedex 5 (France)
2014-11-15
In this work we present an admittance study of a two-dimensional electron gas (2DEG) in the quantum Hall effect (QHE) regime. We have studied several Hall bars in different contacts configurations in the frequency range 100 Hz–1 MHz. Our interpretation is based on the Landauer–Büttiker theory and takes into account both the capacitance and the topology of the coaxial cables which are connected to the sample holder. We show that we always observe losses through the capacitive impedance of the coaxial cables, except in the two contacts configuration in which the cable capacitance does not influence the admittance measurement of the sample. In this case, we measure the electrochemical capacitance of the 2DEG and show its dependence with the filling factor ν.
Error modelling of quantum Hall array resistance standards
Marzano, Martina; Oe, Takehiko; Ortolano, Massimo; Callegaro, Luca; Kaneko, Nobu-Hisa
2018-04-01
Quantum Hall array resistance standards (QHARSs) are integrated circuits composed of interconnected quantum Hall effect elements that allow the realization of virtually arbitrary resistance values. In recent years, techniques were presented to efficiently design QHARS networks. An open problem is that of the evaluation of the accuracy of a QHARS, which is affected by contact and wire resistances. In this work, we present a general and systematic procedure for the error modelling of QHARSs, which is based on modern circuit analysis techniques and Monte Carlo evaluation of the uncertainty. As a practical example, this method of analysis is applied to the characterization of a 1 MΩ QHARS developed by the National Metrology Institute of Japan. Software tools are provided to apply the procedure to other arrays.
Spin Hall effect-driven spin torque in magnetic textures
Manchon, Aurelien; Lee, K.-J.
2011-01-01
Current-induced spin torque and magnetization dynamics in the presence of spin Hall effect in magnetic textures is studied theoretically. The local deviation of the charge current gives rise to a current-induced spin torque of the form (1 - ΒM) × [(u 0 + αH u 0 M) ∇] M, where u0 is the direction of the injected current, H is the Hall angle and is the non-adiabaticity parameter due to spin relaxation. Since αH and ×can have a comparable order of magnitude, we show that this torque can significantly modify the current-induced dynamics of both transverse and vortex walls. © 2011 American Institute of Physics.
From rotating atomic rings to quantum Hall states.
Roncaglia, M; Rizzi, M; Dalibard, J
2011-01-01
Considerable efforts are currently devoted to the preparation of ultracold neutral atoms in the strongly correlated quantum Hall regime. However, the necessary angular momentum is very large and in experiments with rotating traps this means spinning frequencies extremely near to the deconfinement limit; consequently, the required control on parameters turns out to be too stringent. Here we propose instead to follow a dynamic path starting from the gas initially confined in a rotating ring. The large moment of inertia of the ring-shaped fluid facilitates the access to large angular momenta, corresponding to giant vortex states. The trapping potential is then adiabatically transformed into a harmonic confinement, which brings the interacting atomic gas in the desired quantum-Hall regime. We provide numerical evidence that for a broad range of initial angular frequencies, the giant-vortex state is adiabatically connected to the bosonic ν = 1/2 Laughlin state.
Large quantum rings in the ν > 1 quantum Hall regime
International Nuclear Information System (INIS)
Raesaenen, E; Aichinger, M
2009-01-01
We study computationally the ground-state properties of large quantum rings in the filling-factor ν>1 quantum Hall regime. We show that the arrangement of electrons into different Landau levels leads to clear signatures in the total energies as a function of the magnetic field. In this context, we discuss possible approximations for the filling factor ν in the system. We are able to characterize integer-ν states in quantum rings in an analogy with conventional quantum Hall droplets. We also find a partially spin-polarized state between ν = 2 and 3. Despite the specific topology of a quantum ring, this state is strikingly reminiscent of the recently found ν = 5/2 state in a quantum dot.
Large quantum rings in the ν > 1 quantum Hall regime.
Räsänen, E; Aichinger, M
2009-01-14
We study computationally the ground-state properties of large quantum rings in the filling-factor ν>1 quantum Hall regime. We show that the arrangement of electrons into different Landau levels leads to clear signatures in the total energies as a function of the magnetic field. In this context, we discuss possible approximations for the filling factor ν in the system. We are able to characterize integer-ν states in quantum rings in an analogy with conventional quantum Hall droplets. We also find a partially spin-polarized state between ν = 2 and 3. Despite the specific topology of a quantum ring, this state is strikingly reminiscent of the recently found ν = 5/2 state in a quantum dot.
On the quantization of Hall currents in presence of disorder
Combes, J; Hislop, P
2005-01-01
We review recent results of two of the authors concerning the quantization of Hall currents, in particular a general quantization formula for the difference of edge Hall conductances in semi-infinite samples with and without a confining wall. We then study the case where the Fermi energy is located in a region of localized states and discuss new regularizations. We also sketch the proof of localization for 2D-models with constant magnetic field with random potential located in a half-plane in two different situations: 1) with a zero potential in the other half plane and for energies away from the Landau levels and 2) with a confining potential in the other half plane and on an interval of energies that covers an arbitrary number of Landau levels.
Fractional Quantum Hall States in a Ge Quantum Well.
Mironov, O A; d'Ambrumenil, N; Dobbie, A; Leadley, D R; Suslov, A V; Green, E
2016-04-29
Measurements of the Hall and dissipative conductivity of a strained Ge quantum well on a SiGe/(001)Si substrate in the quantum Hall regime are reported. We analyze the results in terms of thermally activated quantum tunneling of carriers from one internal edge state to another across saddle points in the long-range impurity potential. This shows that the gaps for different filling fractions closely follow the dependence predicted by theory. We also find that the estimates of the separation of the edge states at the saddle are in line with the expectations of an electrostatic model in the lowest spin-polarized Landau level (LL), but not in the spin-reversed LL where the density of quasiparticle states is not high enough to accommodate the carriers required.
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...... their activities to a smaller amount of floor space, which would make it possible to have more than one activity on the floor at the same time. Hence, to achieve better utilization during prime time, further analysis and research could focus on how activities in sport halls can be adapted to include more......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...
Quantum Hall effect in epitaxial graphene with permanent magnets
Parmentier, F. D.; Cazimajou, T.; Sekine, Y.; Hibino, H.; Irie, H.; Glattli, D. C.; Kumada, N.; Roulleau, P.
2016-12-01
We have observed the well-kown quantum Hall effect (QHE) in epitaxial graphene grown on silicon carbide (SiC) by using, for the first time, only commercial NdFeB permanent magnets at low temperature. The relatively large and homogeneous magnetic field generated by the magnets, together with the high quality of the epitaxial graphene films, enables the formation of well-developed quantum Hall states at Landau level filling factors v = ±2, commonly observed with superconducting electro-magnets. Furthermore, the chirality of the QHE edge channels can be changed by a top gate. These results demonstrate that basic QHE physics are experimentally accessible in graphene for a fraction of the price of conventional setups using superconducting magnets, which greatly increases the potential of the QHE in graphene for research and applications.
Extraordinary Hall-effect in colloidal magnetic nanoparticle films
Energy Technology Data Exchange (ETDEWEB)
Ben Gur, Leah; Tirosh, Einat [School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 6997801 (Israel); Segal, Amir [School of Physics, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 6997801 (Israel); Markovich, Gil, E-mail: gilmar@post.tau.ac.il [School of Chemistry, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 6997801 (Israel); Gerber, Alexander, E-mail: gerber@post.tau.ac.il [School of Physics, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 6997801 (Israel)
2017-03-15
Colloidal nickel nanoparticles (NPs) coated with polyvinylpyrrolidone (PVP) were synthesized. The nanoparticle dispersions were deposited on substrates and dried under mild heating to form conductive films. The films exhibited very small coercivity, nearly metallic conductivity, and a significant extraordinary Hall effect signal. This method could be useful for preparing simple, printed magnetic field sensors with the advantage of relatively high sensitivity around zero magnetic field, in contrast to magnetoresistive sensors, which have maximal field sensitivity away from zero magnetic field. - Highlights: • Ni nanoparticle ink capable of forming conductive films on drying. • The Ni nanoparticle films exhibit significant extraordinary Hall effect. • This system could be used for preparing printed magnetic field sensors integrated in 3D printed structures.
Spin Hall effect-driven spin torque in magnetic textures
Manchon, Aurelien
2011-07-13
Current-induced spin torque and magnetization dynamics in the presence of spin Hall effect in magnetic textures is studied theoretically. The local deviation of the charge current gives rise to a current-induced spin torque of the form (1 - ΒM) × [(u 0 + αH u 0 M) ∇] M, where u0 is the direction of the injected current, H is the Hall angle and is the non-adiabaticity parameter due to spin relaxation. Since αH and ×can have a comparable order of magnitude, we show that this torque can significantly modify the current-induced dynamics of both transverse and vortex walls. © 2011 American Institute of Physics.
Tearing mode dynamics and sawtooth oscillation in Hall-MHD
Ma, Zhiwei; Zhang, Wei; Wang, Sheng
2017-10-01
Tearing mode instability is one of the most important dynamic processes in space and laboratory plasmas. Hall effects, resulted from the decoupling of electron and ion motions, could cause the fast development and perturbation structure rotation of the tearing mode and become non-negligible. We independently developed high accuracy nonlinear MHD code (CLT) to study Hall effects on the dynamic evolution of tearing modes with Tokamak geometries. It is found that the rotation frequency of the mode in the electron diamagnetic direction is in a good agreement with analytical prediction. The linear growth rate increases with increase of the ion inertial length, which is contradictory to analytical solution in the slab geometry. We further find that the self-consistently generated rotation largely alters the dynamic behavior of the double tearing mode and the sawtooth oscillation. National Magnetic Confinement Fusion Science Program of China under Grant No. 2013GB104004 and 2013GB111004.
Simulating Smoke Filling in Big Halls by Computational Fluid Dynamics
Directory of Open Access Journals (Sweden)
W. K. Chow
2011-01-01
Full Text Available Many tall halls of big space volume were built and, to be built in many construction projects in the Far East, particularly Mainland China, Hong Kong, and Taiwan. Smoke is identified to be the key hazard to handle. Consequently, smoke exhaust systems are specified in the fire code in those areas. An update on applying Computational Fluid Dynamics (CFD in smoke exhaust design will be presented in this paper. Key points to note in CFD simulations on smoke filling due to a fire in a big hall will be discussed. Mathematical aspects concerning of discretization of partial differential equations and algorithms for solving the velocity-pressure linked equations are briefly outlined. Results predicted by CFD with different free boundary conditions are compared with those on room fire tests. Standards on grid size, relaxation factors, convergence criteria, and false diffusion should be set up for numerical experiments with CFD.
Growth of the magnetic field in Hall magnetohydrodynamics
Energy Technology Data Exchange (ETDEWEB)
Nunez, Manuel [Departamento de Analisis Matematico, Universidad de Valladolid, 47005 Valladolid (Spain)
2004-10-01
While the Hall magnetohydrodynamics (MHD) model has been explored in depth in connection with the dispersive waves relevant in magnetic reconnection, a theoretical study of the mathematical features of this system is lacking. We consider here the boundedness of the solutions of the Hall MHD equations. With Dirichlet boundary conditions the total energy of the system is maintained, and dissipated by diffusion, but the behaviour of the higher moments of the magnetic field is more complicated. It is found that certain unusual geometries of the initial condition may lead to a blow-up of the L{sup 3}-norm of the field. Nevertheless, reasonable assumptions upon the correlation between the size of the magnetic field and the curvature of field lines imply that the magnetic field remains uniformly bounded.
Effects of Enhanced Eathode Electron Emission on Hall Thruster Operation
International Nuclear Information System (INIS)
Raitses, Y.; Smirnov, A.; Fisch, N.J.
2009-01-01
Interesting discharge phenomena are observed that have to do with the interaction between the magnetized Hall thruster plasma and the neutralizing cathode. The steadystate parameters of a highly ionized thruster discharge are strongly influenced by the electron supply from the cathode. The enhancement of the cathode electron emission above its self-sustained level affects the discharge current and leads to a dramatic reduction of the plasma divergence and a suppression of large amplitude, low frequency discharge current oscillations usually related to an ionization instability. These effects correlate strongly with the reduction of the voltage drop in the region with the fringing magnetic field between the thruster channel and the cathode. The measured changes of the plasma properties suggest that the electron emission affects the electron cross-field transport in the thruster discharge. These trends are generalized for Hall thrusters of various configurations.
Elastic gauge fields and Hall viscosity of Dirac magnons
Ferreiros, Yago; Vozmediano, María A. H.
2018-02-01
We analyze the coupling of elastic lattice deformations to the magnon degrees of freedom of magnon Dirac materials. For a honeycomb ferromagnet we find that, as happens in the case of graphene, elastic gauge fields appear coupled to the magnon pseudospinors. For deformations that induce constant pseudomagnetic fields, the spectrum around the Dirac nodes splits into pseudo-Landau levels. We show that when a Dzyaloshinskii-Moriya interaction is considered, a topological gap opens in the system and a Chern-Simons effective action for the elastic degrees of freedom is generated. Such a term encodes a phonon Hall viscosity response, entirely generated by quantum fluctuations of magnons living in the vicinity of the Dirac points. The magnon Hall viscosity vanishes at zero temperature, and grows as temperature is raised and the states around the Dirac points are increasingly populated.
On the low-field Hall coefficient of graphite
Directory of Open Access Journals (Sweden)
P. Esquinazi
2014-11-01
Full Text Available We have measured the temperature and magnetic field dependence of the Hall coefficient (RH in three, several micrometer long multigraphene samples of thickness between ∼9 to ∼30 nm in the temperature range 0.1 to 200 K and up to 0.2 T field. The temperature dependence of the longitudinal resistance of two of the samples indicates the contribution from embedded interfaces running parallel to the graphene layers. At low enough temperatures and fields RH is positive in all samples, showing a crossover to negative values at high enough fields and/or temperatures in samples with interfaces contribution. The overall results are compatible with the reported superconducting behavior of embedded interfaces in the graphite structure and indicate that the negative low magnetic field Hall coefficient is not intrinsic of the ideal graphite structure.
Vortices in superconducting films: Statistics and fractional quantum Hall effect
International Nuclear Information System (INIS)
Dziarmaga, J.
1996-01-01
We present a derivation of the Berry phase picked up during exchange of parallel vortices. This derivation is based on the Bogolubov endash de Gennes formalism. The origin of the Magnus force is also critically reanalyzed. The Magnus force can be interpreted as an interaction with the effective magnetic field. The effective magnetic field may be even of the order 10 6 T/A. We discuss a possibility of the fractional quantum Hall effect (FQHE) in vortex systems. As the real magnetic field is varied to drive changes in vortex density, the vortex density will prefer to stay at some quantized values. The mere existence of the FQHE does not depend on vortex quantum statistics, although the pattern of the plateaux does. We also discuss how the density of anyonic vortices can lower the effective strengh of the Magnus force, what might be observable in measurements of Hall resistivity. copyright 1996 The American Physical Society
Local Thermometry of Neutral Modes on the Quantum Hall Edge
Hart, Sean; Venkatachalam, Vivek; Pfeiffer, Loren; West, Ken; Yacoby, Amir
2012-02-01
A system of electrons in two dimensions and strong magnetic fields can be tuned to create a gapped 2D system with one dimensional channels along the edge. Interactions among these edge modes can lead to independent transport of charge and heat, even in opposite directions. Measuring the chirality and transport properties of these charge and heat modes can reveal otherwise hidden structure in the edge. Here, we heat the outer edge of such a quantum Hall system using a quantum point contact. By placing quantum dots upstream and downstream along the edge of the heater, we can measure both the chemical potential and temperature of that edge to study charge and heat transport, respectively. We find that charge is transported exclusively downstream, but heat can be transported upstream when the edge has additional structure related to fractional quantum Hall physics.
Anomalous Hall effect scaling in ferromagnetic thin films
Grigoryan, Vahram L.
2017-10-23
We propose a scaling law for anomalous Hall effect in ferromagnetic thin films. Our approach distinguishes multiple scattering sources, namely, bulk impurity, phonon for Hall resistivity, and most importantly the rough surface contribution to longitudinal resistivity. In stark contrast to earlier laws that rely on temperature- and thickness-dependent fitting coefficients, this scaling law fits the recent experimental data excellently with constant parameters that are independent of temperature and film thickness, strongly indicating that this law captures the underlying physical processes. Based on a few data points, this scaling law can even fit all experimental data in full temperature and thickness range. We apply this law to interpret the experimental data for Fe, Co, and Ni and conclude that (i) the phonon-induced skew scattering is unimportant as expected; (ii) contribution from the impurity-induced skew scattering is negative; (iii) the intrinsic (extrinsic) mechanism dominates in Fe (Co), and both the extrinsic and intrinsic contributions are important in Ni.
Theory of anomalous Hall effect in europium chalcogenides
International Nuclear Information System (INIS)
Sinkkonen, J.
1976-04-01
Considering the exchange interaction between the conduction electrons in a broad 5d-type band and the magnetic electrons in the localized 4f-shells, it is shown that in addition to the ordinary d-f exchange diagonal in band index, there is also a non-diagonal interaction representing a one particle transfer between the conduction and magnetic electrons. Including the spin-orbit coupling, an effective Hamiltonian for the conductionelectrons is obtained, which contains additional asymmetric scattering terms. The ordinary d-f exchange is treated as the dominating scattering interaction. The anomatous Hall effect results by skew scattering and side jump mechanisms. The density matrix method is used to derive the transport properties. The effect of the correlation of spins at different lattice sites is discussed. The model indicates that the anomatous Hall effect can be seen in heavily doped samples. (author)
Anomalous Hall effect in ZrTe5
Liang, Tian; Lin, Jingjing; Gibson, Quinn; Kushwaha, Satya; Liu, Minhao; Wang, Wudi; Xiong, Hongyu; Sobota, Jonathan A.; Hashimoto, Makoto; Kirchmann, Patrick S.; Shen, Zhi-Xun; Cava, R. J.; Ong, N. P.
2018-05-01
Research in topological matter has expanded to include the Dirac and Weyl semimetals1-10, which feature three-dimensional Dirac states protected by symmetry. Zirconium pentatelluride has been of recent interest as a potential Dirac or Weyl semimetal material. Here, we report the results of experiments performed by in situ three-dimensional double-axis rotation to extract the full 4π solid angular dependence of the transport properties. A clear anomalous Hall effect is detected in every sample studied, with no magnetic ordering observed in the system to the experimental sensitivity of torque magnetometry. Large anomalous Hall signals develop when the magnetic field is rotated in the plane of the stacked quasi-two-dimensional layers, with the values vanishing above about 60 K, where the negative longitudinal magnetoresistance also disappears. This suggests a close relation in their origins, which we attribute to the Berry curvature generated by the Weyl nodes.
Valley Hall effect and Nernst effect in strain engineered graphene
Niu, Zhi Ping; Yao, Jian-ming
2018-04-01
We theoretically predict the existence of tunneling valley Hall effect and Nernst effect in the normal/strain/normal graphene junctions, where a strained graphene is sandwiched by two normal graphene electrodes. By applying an electric bias a pure transverse valley Hall current with longitudinal charge current is generated. If the system is driven by a temperature bias, a valley Nernst effect is observed, where a pure transverse valley current without charge current propagates. Furthermore, the transverse valley current can be modulated by the Fermi energy and crystallographic orientation. When the magnetic field is further considered, we obtain a fully valley-polarized current. It is expected these features may be helpful in the design of the controllable valleytronic devices.
Effect of quantum tunneling on spin Hall magnetoresistance.
Ok, Seulgi; Chen, Wei; Sigrist, Manfred; Manske, Dirk
2017-02-22
We present a formalism that simultaneously incorporates the effect of quantum tunneling and spin diffusion on the spin Hall magnetoresistance observed in normal metal/ferromagnetic insulator bilayers (such as Pt/Y 3 Fe 5 O 12 ) and normal metal/ferromagnetic metal bilayers (such as Pt/Co), in which the angle of magnetization influences the magnetoresistance of the normal metal. In the normal metal side the spin diffusion is known to affect the landscape of the spin accumulation caused by spin Hall effect and subsequently the magnetoresistance, while on the ferromagnet side the quantum tunneling effect is detrimental to the interface spin current which also affects the spin accumulation. The influence of generic material properties such as spin diffusion length, layer thickness, interface coupling, and insulating gap can be quantified in a unified manner, and experiments that reveal the quantum feature of the magnetoresistance are suggested.
Edge states in quantum Hall effect in graphene
International Nuclear Information System (INIS)
Gusynin, V.P.; Miransky, V.A.; Sharapov, S.G.; Shovkovy, I.A.
2008-01-01
We review recent results concerning the spectrum of edge states in the quantum Hall effect in graphene. In particular, special attention is paid to the derivation of the conditions under which gapless edge states exist in the spectrum of graphene with 'zigzag' and 'armchair' edges. It is found that in the case of a half-plane or a ribbon with zigzag edges, there are gapless edge states only when a spin gap dominates over a Dirac mass gap. In the case of a half-plane with an armchair edge, the existence of the gapless edge states depends on the specific type of Dirac mass gaps. The implications of these results for the dynamics in the quantum Hall effect in graphene are discussed
Anomalous Hall effect and Nernst effect in itinerant ferromagnets
International Nuclear Information System (INIS)
Miyasato, T.; Abe, N.; Fujii, T.; Asamitsu, A.; Onose, Y.; Onoda, S.; Nagaosa, N.; Tokura, Y.
2007-01-01
Anomalous Hall effect (AHE) and anomalous Nernst effect (ANE) in many ferromagnetic metals including pure metals, oxides, and chalcogenides, are studied to obtain unified understandings of their origins. We show the universal behavior of anomalous Hall conductivity σ xy as a function of longitudinal conductivity σ xx over six orders of magnitude, which is well reproduced by a recent theory assuming both the intrinsic and extrinsic contributions to the AHE. ANE is closely related with AHE and gives us further information about the electronic state in the ground state of ferromagnets. The temperature dependence of transverse Peltier coefficient α xy shows almost similar behavior among various ferromagnets, and this behavior is expected from a conventional Boltzmann transport theory
Anomalous Hall effect scaling in ferromagnetic thin films
Grigoryan, Vahram L.; Xiao, Jiang; Wang, Xuhui; Xia, Ke
2017-01-01
We propose a scaling law for anomalous Hall effect in ferromagnetic thin films. Our approach distinguishes multiple scattering sources, namely, bulk impurity, phonon for Hall resistivity, and most importantly the rough surface contribution to longitudinal resistivity. In stark contrast to earlier laws that rely on temperature- and thickness-dependent fitting coefficients, this scaling law fits the recent experimental data excellently with constant parameters that are independent of temperature and film thickness, strongly indicating that this law captures the underlying physical processes. Based on a few data points, this scaling law can even fit all experimental data in full temperature and thickness range. We apply this law to interpret the experimental data for Fe, Co, and Ni and conclude that (i) the phonon-induced skew scattering is unimportant as expected; (ii) contribution from the impurity-induced skew scattering is negative; (iii) the intrinsic (extrinsic) mechanism dominates in Fe (Co), and both the extrinsic and intrinsic contributions are important in Ni.
Air leakage test of reactor hall using tracer technique
International Nuclear Information System (INIS)
Yang Yanqiu; Yang Liang; Yang Tongzai
2011-01-01
The leakage ratios of three related reactor halls were tested by sulfur hexafluoride gaseous tracer technique. Moreover, the accumulation intensities of leak gas and its retention time in some important working rooms, the crossroads of corridors and anteroom of the building were detected. The results show that the air leakage ratios of the three reactor halls are (7.30±0.16) x 10 -4 , (1.88±0.12) x 10 -4 and (2.07±0.07) x 10 -4 h -1 . The leak gas accumulates in all the detected working rooms fast, and the retention time to various rooms is about 5 h. The heaviest intensities are in the clothes change rooms on the first floor. However, the retention time to the crossroads and the anteroom is about 10 h, and the accumulation intensities are much small. (authors)
Carbon Back Sputter Modeling for Hall Thruster Testing
Gilland, James H.; Williams, George J.; Burt, Jonathan M.; Yim, John T.
2016-01-01
In support of wear testing for the Hall Effect Rocket with Magnetic Shielding (HERMeS) program, the back sputter from a Hall effect thruster plume has been modeled for the NASA Glenn Research Centers Vacuum Facility 5. The predicted wear at a near-worst case condition of 600 V, 12.5 kW was found to be on the order of 3 4 mkhour in a fully carbon-lined chamber. A more detailed numerical monte carlo code was also modified to estimate back sputter for a detailed facility and pumping configuration. This code demonstrated similar back sputter rate distributions, but is not yet accurately modeling the magnitudes. The modeling has been benchmarked to recent HERMeS wear testing, using multiple microbalance measurements. These recent measurements have yielded values, on the order of 1.5- 2 microns/khour.
Argon spill in the hall of the ATLAS experiment
Peón-Hernández, G
1998-01-01
A hazard analysis is in progress to determine the operation mode of the ventilation system in the ATLAS hall in case of an Argon spill. Two risk scenarios have been investigated so far. In the first, the behaviour of an Argon gas pool is calculated for different ventilation strategies. In the second, the behaviour of Argon gas leaking from the bottom part of the detector is studied for different flows. The description of the study, results and conclusions are presented.
Measurement of Safety Factor Using Hall Probes on CASTOR Tokamak
Czech Academy of Sciences Publication Activity Database
Kovařík, Karel; Ďuran, Ivan; Bolshakova, I.; Holyaka, R.; Erashok, V.
2006-01-01
Roč. 56, suppl.B (2006), s. 104-110 ISSN 0011-4626. [Symposium on Plasma Physics and Technology/22nd./. Praha, 26.6.2006-29.6.2006] R&D Projects: GA AV ČR(CZ) KJB100430504 Institutional research plan: CEZ:AV0Z20430508 Keywords : Plasma * tokamak * safety factor * hall probe Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 0.568, year: 2006
Data handling for the wide-angle hall jet experiment
International Nuclear Information System (INIS)
Cassel, D.; Engelmann, R.; Gordon, H.; Grannis, P.; Mallik, U.; Meadows, B.; Morris, T.; Plano, R.; Saulys, A.; Stein, S.
1978-01-01
The data handling needs for a jet production experiment in the wide-angle hall are discussed. The several layers of triggering and a data acquisition system were designed, the configuration of the local intersection computer system was discussed, and the time required to analyze a typical event was estimated. It was concluded that the experiment does not appear to place unrealistic demands on detector technology. The slow trigger was believed to be the crucial aspect of the experiment. 15 figures, 1 tables
Options for Energy Upgrade of the Hall B Tagger
International Nuclear Information System (INIS)
H. Crannell; D. Sober
1998-01-01
Four options for an energy upgrade of the present Hall-B Tagger have been considered. These are: (1) Boost the magnetic field in the present Tagger; (2) Replace the Tagger with a new Tagger system; (3) Install a pre-Tagger magnetic chacain, and (4) Use the present Tagger as part of the beam dump. In this document each of these options is described briefly, the advantages and disadvantages of each are presented, and a very rough cost of implementation is suggested
Hall Effect Influence on a Highly Conducting Fluid
Energy Technology Data Exchange (ETDEWEB)
Witalis, E A
1966-11-15
The properties of an incompressible perfect fluid exhibiting Hall effect is investigated in the limit of infinite electrical conductivity and mobility. The magnetic field strength and the fluid velocity are found to obey the equations B = {mu}{rho}/{sigma} x curlV and V -{mu}/({sigma}{mu}{sub 0}) x curlB (MKS units) where {rho}, {sigma} and {mu} denote mass density, conductivity and charge carrier mobility. Some physical interpretations and applications are given.
Levitation and percolation in quantum Hall systems with correlated disorder
Song, Hui; Maruyama, Isao; Hatsugai, Yasuhiro
2007-01-01
We investigate the integer quantum Hall system in a two dimensional lattice model with spatially correlated disorder by using the efficient method to calculate the Chern number proposed by Fukui et al. [J. Phys. Soc. Jpn. 74, 1674 (2005)]. Distribution of charge density indicates that the extended states at the center of each Landau band have percolating current paths, which are topologically equivalent to the edge states that exist in a system with boundaries. As increasing the strength of d...
Resistive mode in rotating plasma columns including the hall current
International Nuclear Information System (INIS)
Galvao, R.M.O.
1983-01-01
A new resistive mode is shown to exist in rotating plasma columns. The mode is localized in the neighbourhood of the radius where the angular velocity of the bulk plasma is equal to minus half the local angular velocity of the ions. This singular point is caused by the Hall term in the generalized Ohm law. The growth rate of the mode scales with eta sup(1/2), where eta is the plasma resistivity. (Author) [pt
Focused ion beam patterned Hall nano-sensors
International Nuclear Information System (INIS)
Candini, A.; Gazzadi, G.C.; Di Bona, A.; Affronte, M.; Ercolani, D.; Biasiol, G.; Sorba, L.
2007-01-01
By means of focused ion beam milling, we fabricate Hall magnetometers with active areas as small as 100x100nm 2 . The constituent material can either be metallic (Au), semimetallic (Bi) or doped bulk semiconducting (Si doped GaAs). We experimentally show that Au nano-probes can work from room temperature down to liquid helium with magnetic flux sensitivity -1 Φ 0
Tunneling between edge states in a quantum spin Hall system.
Ström, Anders; Johannesson, Henrik
2009-03-06
We analyze a quantum spin Hall device with a point contact connecting two of its edges. The contact supports a net spin tunneling current that can be probed experimentally via a two-terminal resistance measurement. We find that the low-bias tunneling current and the differential conductance exhibit scaling with voltage and temperature that depend nonlinearly on the strength of the electron-electron interaction.
Nanoconstriction spin-Hall oscillator with perpendicular magnetic anisotropy
Divinskiy, B.; Demidov, V. E.; Kozhanov, A.; Rinkevich, A. B.; Demokritov, S. O.; Urazhdin, S.
2017-07-01
We experimentally study spin-Hall nano-oscillators based on [Co/Ni] multilayers with perpendicular magnetic anisotropy. We show that these devices exhibit single-frequency auto-oscillations at current densities comparable to those for in-plane magnetized oscillators. The demonstrated oscillators exhibit large magnetization precession amplitudes, and their oscillation frequency is highly tunable by the electric current. These features make them promising for applications in high-speed integrated microwave circuits.
Two-dimensional Ising physics in quantum Hall ferromagnets
Czech Academy of Sciences Publication Activity Database
Jungwirth, Tomáš; MacDonald, A. H.; Rezayi, E. H.
2002-01-01
Roč. 12, - (2002), s. 1-7 ISSN 1386-9477 R&D Projects: GA ČR GA202/01/0754; GA MŠk OC 514.10 Institutional research plan: CEZ:AV0Z1010914 Keywords : quantum Hall ferromagnets * higher Landau levels * domain walls Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.107, year: 2002
Single-electron quantum tomography in quantum Hall edge channels
International Nuclear Information System (INIS)
Grenier, Ch; Degiovanni, P; Herve, R; Bocquillon, E; Parmentier, F D; Placais, B; Berroir, J M; Feve, G
2011-01-01
We propose a quantum tomography protocol to measure single-electron coherence in quantum Hall edge channels, and therefore access for the first time the wavefunction of single-electron excitations propagating in ballistic quantum conductors. Its implementation would open the way to quantitative studies of single-electron decoherence and would provide a quantitative tool for analyzing single- to few-electron sources. We show how this protocol could be implemented using ultrahigh-sensitivity noise measurement schemes.