scholarly journals Controllable valley filter in graphene topological line defect with magnetic field

2020 ◽  
Author(s):  
Hongyu Tian ◽  
Chongdan Ren ◽  
Benhu Zhou ◽  
Weitao Lu ◽  
Yunfang Li ◽  
...  
Keyword(s):  
Magnetic Field ◽  
The Other ◽  
Local Magnetic Field ◽  
Line Defect ◽  
Simple Scheme ◽  
Experimental Realization ◽  
Injection Angle ◽  
High Incidence ◽  
Valley Polarization ◽  
Peak Transmission

Abstract The extended line defect of graphene is an extraordinary candidate in valleytronics while the high valley polarization can only occur for electrons with high incidence angles which brings about tremendous challenges to experimental realization. In this paper, we propose a simple scheme to filter one conical valley state by applying a local magnetic field. It is found that due to the movement of the Dirac points, the transmission profiles of the two valleys are shifted along the injection-angle axis at the same pace, resulting in the peak transmission of one valley state being reduced drastically while remaining unaffected for the other valley state, which induces nearly perfect valley polarization. This scheme can be easily implemented in experiments and plays a key role in graphene valleytronics.

Local magnetic field distribution in polycrystalline YBa2Cu3O7 and its influence on bulk critical currents

1991 ◽  
Vol 6 (6) ◽  
pp. 1135-1147 ◽  
Author(s):  
Thomas R. Askew ◽  
Richard B. Flippen ◽  
Kevin J. Leary ◽  
Milind N. Kunchur
Keyword(s):  
Magnetic Field ◽  
Simple Model ◽  
Critical Current Density ◽  
Field Distribution ◽  
Critical Currents ◽  
The Other ◽  
Magnetic Field Distribution ◽  
Local Magnetic Field ◽  
Transport Critical Current Density ◽  
High Quality

The transport critical current density Jc has been measured in high quality polycrystalline YBa2Cu3O7 samples made from extruded preforms. The hysteretic response of Jc to applied magnetic fields was studied as a function of temperature (77–87 K) and sample morphology for various field sweeps in the 0–5 KOe range. A variety of samples show a basic Jc ∼ H−n behavior where n depends on temperature, but is independent of the other variables. A simple model of the local magnetic field distribution is presented and compared to the data, and the theoretical implications of the power law behavior are considered.

scholarly journals PICO-SATELLITE DETUMBLING SIMULATION USING MAGNETIC ATITUDE ACTUATOR (SIMULASI DETUMBLING PADA SATELIT PIKO MENGGUNAKAN AKTUATOR SIKAP MAGNETIK)

2017 ◽  
Vol 15 (1) ◽  
pp. 11 ◽  
Author(s):  
Ali Muksin ◽  
Ridanto Eko Poetro ◽  
Robertus Heru Triharjanto
Keyword(s):  
Magnetic Field ◽  
Control System ◽  
Attitude Control ◽  
The Other ◽  
Local Magnetic Field ◽  
Control Law ◽  
Attitude Control System ◽  
Transient Time ◽  
Matlab Simulink ◽  
The Moment

One of the methods to control Nano/pico-satellite’s attitude is using magneto-torquers as attitude actuators. ITB, at the moment is planning to develop a cubesat. Therefore, the objective of the research was to investigate the performance of such attitude control system for 3U class cubesat. The research used Matlab/simulink-based satellite simulator developed by LAPAN and ITB, and B-dot control law. The advantages of the method are that the actuators are small and lighter compared to the other type of actuators, such as momentum wheels or reaction wheels. However, the disadvantages is that the torques can be created only when the actuator oriented at non-zero angle with local magnetic field. The results showed that the attitude control system could performed the detumbling operation, with the best transient time at about two orbits period. Varying the gain parameter in the controller may result into variation of transient time and even unstability.   AbstrakSalah satu cara untuk mengendalikan sikap satelit nano/piko adalah dengan menggunakan magneto-torquer sebagai aktuator. Saat ini ITB tengah mewacanakan pengembangan cubesat, sehinggga tujuan dari penelitian ini adalah untuk mengevaluasi kinerja sistem kendali sikap berdasarkan medan magnet Bumi pada cubesat kelas 3U. Penelitian ini menggunakan simulator satelit berbasis MATLAB/simulink yang dikembangkan oleh LAPAN dan ITB, moda kendalinya berbasis hukum kendali b-dot. Keuntungan dari sistem kendali ini adalah ukuran dan beratnya yang kecil, dibandingkan dengan moda kendali lain, seperti momentum wheel atau reaction wheel. Sementara kerugiannya adalah hanya bisa menghasilkan torsi saat aktuator mempunyai sudut tidak nol dengan medan magnet Bumi. Hasil menunjukkan bahwa moda kendali tersebut dapat melakukan manuver de-tumbling, dengan waktu transient terbaik mendekati dua periode orbit. Juga ditunjukkan bahwa variasi waktu transient dan ketidakstabilan dapat diperoleh dengan memvariasikan parameter gain pada kontroler. 

scholarly journals Ground state and stability of the fractional plateau phase in metallic Shastry–Sutherland system TmB4

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Matúš Orendáč ◽  
Slavomír Gabáni ◽  
Pavol Farkašovský ◽  
Emil Gažo ◽  
Jozef Kačmarčík ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Phase Diagram ◽  
Ground State ◽  
Constant Magnetic Field ◽  
Paramagnetic Phase ◽  
The Other ◽  
Zero Field ◽  
Plateau Phase ◽  
Low Field ◽  
Zero Field Cooling

AbstractWe present a study of the ground state and stability of the fractional plateau phase (FPP) with M/Msat = 1/8 in the metallic Shastry–Sutherland system TmB4. Magnetization (M) measurements show that the FPP states are thermodynamically stable when the sample is cooled in constant magnetic field from the paramagnetic phase to the ordered one at 2 K. On the other hand, after zero-field cooling and subsequent magnetization these states appear to be of dynamic origin. In this case the FPP states are closely associated with the half plateau phase (HPP, M/Msat = ½), mediate the HPP to the low-field antiferromagnetic (AF) phase and depend on the thermodynamic history. Thus, in the same place of the phase diagram both, the stable and the metastable (dynamic) fractional plateau (FP) states, can be observed, depending on the way they are reached. In case of metastable FP states thermodynamic paths are identified that lead to very flat fractional plateaus in the FPP. Moreover, with a further decrease of magnetic field also the low-field AF phase becomes influenced and exhibits a plateau of the order of 1/1000 Msat.

Relative Distribution and Incidence of Viruses Associated with Disease Outbreaks in Tomato Fields in Trinidad

2006 ◽  
Vol 7 (1) ◽  
pp. 29
Author(s):  
S. N. Rampersad
Keyword(s):  
Production Systems ◽  
Management Strategies ◽  
Disease Outbreaks ◽  
Tobacco Etch Virus ◽  
The Other ◽  
Multiple Infections ◽  
Relative Distribution ◽  
Tomato Production ◽  
Viral Pathogen ◽  
High Incidence

Tomato production in Trinidad has suffered considerable losses in yield and fruit quality due to infections of hitherto surmised etiology. In order to develop strategies for controlling viral diseases in tomato, the relative distribution and incidence of seven viruses that commonly infect tomato were determined. Of the 362 samples tested, Potato yellow mosaic Trinidad virus (PYMTV) was found in every farm except two and was present at relatively high incidence throughout the country. Tobacco mosaic virus (TMV) and Tobacco etch virus (TEV) were found in fewer farms and at lower incidences while the other viruses were absent. Single infections of either virus were more common than double infections and multiple infections were rare but present. The results indicated that PYMTV is the predominant and most important viral pathogen in tomato production systems in Trinidad; however, begomovirus disease management strategies will also have to accommodate controls Accepted for publication 10 January 2006. Published 9 March 2006.

Magnetocrystalline Anisotropy and Twinning Stress of 10M and 2M Martensites in Ni-Mn-Ga System

2006 ◽  
Vol 512 ◽  
pp. 195-200 ◽  
Author(s):  
Nariaki Okamoto ◽  
Takashi Fukuda ◽  
Tomoyuki Kakeshita ◽  
Tetsuya Takeuchi
Keyword(s):  
Magnetic Field ◽  
Shear Stress ◽  
Magnetocrystalline Anisotropy ◽  
Anisotropy Constant ◽  
The Other ◽  
Magnetic Shear ◽  
Maximum Value ◽  
Twinning Plane ◽  
Twinning Shear ◽  
The Difference

Ni2MnGa alloy with 10M martensite exhibits rearrangement of martensite variants (RMV) by magnetic field, but Ni2.14Mn0.92Ga0.94 with 2M martensite does not. In order to explain the difference, we measured uniaxial magnetocrystalline anisotropy constant Ku and the stress required for twinning plane movement τreq in these alloys. Concerning the former alloy, the maximum value of magnetic shear stress acting across twinning plane τmag, which is evaluated as |Ku| divided by twinning shear, becomes larger than τr eq. On the other hand, concerning the latter alloy, the maximum of τmag is only one-tenth of τreq at any temperature examined. Obviously, the relation, τmag> τr eq, is satisfied when RMV occurs by magnetic field and vice versa. In this martensite, the large twinning shear of 2M martensite is responsible for small τmag and large τreq.

scholarly journals THE ENERGY EIGENVALUES OF THE TWO DIMENSIONAL HYDROGEN ATOM IN A MAGNETIC FIELD

2006 ◽  
Vol 15 (06) ◽  
pp. 1263-1271 ◽  
Author(s):  
A. SOYLU ◽  
O. BAYRAK ◽  
I. BOZTOSUN
Keyword(s):  
Magnetic Field ◽  
Hydrogen Atom ◽  
Iteration Method ◽  
Weak Magnetic Field ◽  
The Other ◽  
Asymptotic Iteration Method ◽  
Iterative Approach ◽  
Two Dimensional ◽  
Energy Eigenvalues ◽  
The Magnetic Field

In this paper, the energy eigenvalues of the two dimensional hydrogen atom are presented for the arbitrary Larmor frequencies by using the asymptotic iteration method. We first show the energy eigenvalues for the case with no magnetic field analytically, and then we obtain the energy eigenvalues for the strong and weak magnetic field cases within an iterative approach for n=2-10 and m=0-1 states for several different arbitrary Larmor frequencies. The effect of the magnetic field on the energy eigenvalues is determined precisely. The results are in excellent agreement with the findings of the other methods and our method works for the cases where the others fail.

scholarly journals Motional Stark Effect measurements of the local magnetic field in high temperature fusion plasmas

2015 ◽  
Vol 10 (10) ◽  
pp. P10008-P10008 ◽  
Author(s):  
R.C. Wolf ◽  
A. Bock ◽  
O.P. Ford ◽  
R. Reimer ◽  
A. Burckhart ◽  
...  
Keyword(s):  
Magnetic Field ◽  
High Temperature ◽  
Stark Effect ◽  
Local Magnetic Field ◽  
Fusion Plasmas ◽  
Motional Stark Effect

How “Native” Are Heritage Speakers?

2013 ◽  
Vol 10 (2) ◽  
pp. 153-177 ◽  
Author(s):  
Silvina Montrul
Keyword(s):  
Language Learning ◽  
Experimental Evidence ◽  
Native Speakers ◽  
Learning Experience ◽  
Age Of Acquisition ◽  
The Other ◽  
Gender Agreement ◽  
Heritage Speakers ◽  
High Incidence ◽  
Incomplete Acquisition

One of the chief characteristics of heritage speakers is that they range in proficiency from “overhearers” to “native” speakers. To date, the vast majority of linguistic and psycholinguistic studies have characterized the non-target-like linguistic abilities of heritage speakers as a product of incomplete acquisition and/or attrition due to reduced exposure and opportunities to use the language during childhood. This article focuses on the other side of the problem, emphasizing instead the high incidence of native-like abilities in adult heritage speakers. I illustrate this issue with recent experimental evidence from gender agreement in Spanish, a grammatical feature that is mastered at almost 100% accuracy in production by native speakers;yet it is one of the most difficult areas to master for non-native speakers, including near-natives.I discuss how age of acquisition and language-learning experience explain these effects.

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