Effect of Local Magnetic Moments on the Metallic Behavior in Two Dimensions

The temperature dependence of conductivity $\sigma (T)$ in the metallic phase of a two-dimensional electron system in silicon has been studied for different concentrations of local magnetic moments. The local moments have been induced by disorder, and their number was varied using substrate bias. The data suggest that in the limit of $T\to 0$ the metallic behavior, as characterized by $d\sigma/dT < 0$, is suppressed by an arbitrarily small amount of scattering by local magnetic moments.Comment: 4 pages, revtex, plus four encapsulated postscript figure

Mesoscopic Behavior Near a Two-Dimensional Metal-Insulator Transition

We study conductance fluctuations in a two-dimensional electron gas as a function of chemical potential (or gate voltage) from the strongly insulating to the metallic regime. Power spectra of the fluctuations decay with two distinct exponents (1/v_l and 1/v_h). For conductivity $\sigma\sim 0.1 e^{2}/h$, we find a third exponent (1/v_i) in the shortest samples, and non-monotonic dependence of v_i and v_l on \sigma. We study the dependence of v_i, v_l, v_h, and the variances of corresponding fluctuations on \sigma, sample size, and temperature. The anomalies near $\sigma\simeq 0.1 e^{2}/h$ indicate that the dielectric response and screening length are critically behaved, i.e. that Coulomb correlations dominate the physics.Comment: Revised according to referee remark

Conductance Fluctuations Near the Two-Dimensional Metal-Insulator Transition

Measurements of conductance $G$ on short, wide, high-mobility Si-MOSFETs reveal both a two-dimensional metal-insulator transition (MIT) at moderate temperatures (1 $<~ T <$ 4~K) and mesoscopic fluctuations of the conductance at low temperatures ($T~ <$ 1~K). Both were studied as a function of chemical potential (carrier concentration $n_s$) controlled by gate voltage ($V_g$) and magnetic field $B$ near the MIT. Fourier analysis of the low temperature fluctuations reveals several fluctuation scales in $V_g$ that vary non-monotonically near the MIT. At higher temperatures, $G(V_g,B)$ is similar to large FETs and exhibits a MIT. All of the observations support the suggestion that the MIT is driven by Coulomb interactions among the carriers.Comment: 4 pages, LaTeX, physica.sty (slightly modified prabib.sty), Submitted to the 1997 Conference on Electronic Properties of Two-Dimensional System

Supplementary data for article: Kop, T.; Bjelaković, M.; Milić, D. Synthesis and Properties of Bis(Pyrrolidino)Fullerenes Bridged by a Flexible Alkyl-Tether. Tetrahedron 2015, 71 (29), 4801–4809. https://doi.org/10.1016/j.tet.2015.05.038

Supplementary material for: [https://doi.org/10.1016/j.tet.2015.05.038]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/1729

Shifting from Ideal to Critical Multiculturalism in Canadian Teacher Education Programs: Examining the Challenges

This paper describes a recent initiative designed to provide support for teacher candidates from culturally diverse backgrounds as they traverse a one-year teacher education program in Canada. Results and discussion are based on qualitative data from an information survey, student-professor conversations, a review of seminar documents and processes, and observations and reflections made by professors conducting the seminar. Overall, the Language and Cultural Engagement Seminar was successful in providing a supportive environment in which complicated and politically volatile issues, which would otherwise have remained unacknowledged, were discussed openly. The main concerns expressed by participants were the communication concern (grammar, vocabulary, pronunciation, accent, etc.), concern for power and authority in the classroom, and the socio-cultural acceptance concern. Power and communication concerns diminished when teacher candidates felt a level of cultural acceptance in the classroom; therefore, we propose that socio-cultural acceptance be investigated in future research into the concern construct. Since differential pronunciation had the effect of positioning teacher candidates on the periphery of classroom discourse, we concluded that acceptance of accent diversity (lack thereof) was one barrier between ideal (policy) and experienced (lived) multi-cultures. Cet article décrit une initiative récente désignée à procurer un soutien aux étudiants-maîtres provenant de divers milieux socio-culturels pendant l\u27année de leur formation au Canada. Les résultats et les discussions sont basés sur les données qualitatives obtenues d\u27une surveillance de renseignements, des conversations entre professeurs et étudiants, une revision des documents et processus obtenus pendant un colloque et des observations et réflexions faites par les professeurs conduisant ce colloque. En général le colloque Language and Cultural Engagement Seminar a réussi à offrir un mileu positif dans lequel des problèmes compliqués ou explosifs, qui auraient pu passer inapperçus, avaient été discutés franchement. Les principales inquiétudes citées par les participants sont: l\u27inquiétude sur la communication (grammaire, vocabulaire, prononciation, accent, etc.), l\u27inquiétude concernant l\u27autorité et le pouvoir en classe. et l\u27inquiétude de n\u27être pas acceptés à cause de leurs antécédents socio-culturels. Mais les inquiétudes sur le pouvoir et la communication sont diminuées quand les étudiants-maîtres sentaient qu\u27ils atteignaient un certain niveau d\u27acceptation culturelle en classe. Nous proposons que l\u27acceptation socio-culturelle deviendra un sujet de recherche plus poussé dans l\u27avenir. Comme la prononciation différentielle avait l\u27effet de placer les instituteurs aux périphéries du discours en classe, nous avions conclu que l\u27acceptation des accents divers (ou le manque de) est une barrière entre l\u27idéal (politique) et l\u27expérience (vécue) d\u27un milieu à cultures multiples