217 research outputs found

    Computer-aided Circuit Analysis Semiannual Report, May 15 - Nov. 14, 1966

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    Digital computer aided circuit analysis and desig

    Computer-aided circuit analysis Annual report, May 15, 1965 - May 14, 1966

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    Research on digital computer aided analysis of electric circuit

    Tuning of metal-insulator transition of two-dimensional electrons at parylene/SrTiO3_3 interface by electric field

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    Electrostatic carrier doping using a field-effect-transistor structure is an intriguing approach to explore electronic phases by critical control of carrier concentration. We demonstrate the reversible control of the insulator-metal transition (IMT) in a two dimensional (2D) electron gas at the interface of insulating SrTiO3_3 single crystals. Superconductivity was observed in a limited number of devices doped far beyond the IMT, which may imply the presence of 2D metal-superconductor transition. This realization of a two-dimensional metallic state on the most widely-used perovskite oxide is the best manifestation of the potential of oxide electronics

    Dynein structure and power stroke

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    Dynein ATPases are microtubule motors that are critical to diverse processes such as vesicle transport and the beating of sperm tails; however, their mechanism of force generation is unknown. Each dynein comprises a head, from which a stalk and a stem emerge. Here we use electron microscopy and image processing to reveal new structural details of dynein c, an isoform from Chlamydomonas reinhardtii flagella, at the start and end of its power stroke. Both stem and stalk are flexible, and the stem connects to the head by means of a linker approximately 10 nm long that we propose lies across the head. With both ADP and vanadate bound, the stem and stalk emerge from the head 10 nm apart. However, without nucleotide they emerge much closer together owing to a change in linker orientation, and the coiled-coil stalk becomes stiffer. The net result is a shortening of the molecule coupled to an approximately 15-nm displacement of the tip of the stalk. These changes indicate a mechanism for the dynein power stroke

    Two-dimensional superconductivity at a Mott-Insulator/Band-Insulator interface: LaTiO3/SrTiO3

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    Transition metal oxides display a great variety of quantum electronic behaviours where correlations often play an important role. The achievement of high quality epitaxial interfaces involving such materials gives a unique opportunity to engineer artificial structures where new electronic orders take place. One of the most striking result in this area is the recent observation of a two-dimensional electron gas at the interface between a strongly correlated Mott insulator LaTiO3 and a band insulator SrTiO3. The mechanism responsible for such a behaviour is still under debate. In particular, the influence of the nature of the insulator has to be clarified. Here we show that despite the expected electronic correlations, LaTiO3/SrTiO3 heterostructures undergo a superconducting transition at a critical temperature Tc=300 mK. We have found that the superconducting electron gas is confined over a typical thickness of 12 nm. We discuss the electronic properties of this system and review the possible scenarios

    Components of Effective Leadership

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    [First paragraph] The effective schools literature demonstrates that the principal\u27s leadership is key to the revitalization of schools. The purpose of this article is to feature those components of leadership on which principals need to place attention and to provide suggested activities to enhance these components

    Leadership Styles

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    [First paragraph] Effective schools literature shows clearly that the leadership of the principal is key to the effectiveness of the school (Hoy and Miskell, 1982, and Arnn and Mangieri, 1988). To be effective, principals must use leadership styles appropriate to the situation

    Grievances

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    [First Paragraph] The Virginia Board of Education has adopted a procedure for resolving disputes concerning the application of local board policies, rules, and regulations as they impact the work or disciplinary actions of teachers. It is vital that the principal be aware of the process and the timeline involved in the grievance procedure since the solution should be secured at the lowest administrative level in the process. It is beyond the scope of this article to provide every detail of the grievance process. For a complete detailing of procedure, please refer to Chapter 15, Article 3, Sections 22.1-306 through 22.1-314 of the Code of Virginia
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