968 resultados para Hall, Gordon, 1784-1826.


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利用GaAs衬底上的InAa薄膜制备的Hall器件,具有灵敏度高(在相同的电子浓度、室温附近灵敏度是GaAs Hall器件的1.5倍),不等位电压温漂小等优点。可用于电流传感器、无刷电机等磁敏传感器中,具有广阔的应用前景。

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于2010-11-23批量导入

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报道了利用InAs外延薄膜制作霍尔器件,通过分子束外延技术在GaAs衬底上生长的InAs薄膜具有较高的迁移率和较好的温度特性。用这种材料制作的霍尔器件在每千欧姆内阻条件下灵敏度与GaAs平面Hall器件相比提高了50%。

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The topological state and the total topological index, tau, have been tested systematically. Counterexamples are provided proving that the topological state method cannot determine classes of symmetrically equivalent atoms in a molecule fully correct. The

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Grattan J.P., Rabartin, R., Self, S. & Thordarson, Th. 2005. Volcanic air pollution and mortality in France 1783-84. Comptes Rendu Geosciences. 641-651 This item is available in both English and French in the PDF file.

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Jenkins, G.; Jones, F.; and Jones, D. (Eds.). (2007). The Correspondence of Iolo Morganwg: Vols. I, II and III. Cardiff: University of Wales Press. RAE2008

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http://books.google.com/books?vid=OCLC00289131

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The Edmund Irwin Gordon papers document Gordon’s studies and professional work. The collection contains correspondence, EIG’s writings for publication and otherwise, course materials from the University of Pennsylvania and teaching at Harvard University, photographs of tablets and from digs, translations and notes from writings and tablets in ancient languages, forms and papers related to various grants, and materials from EIG’s work in Signal Intelligence during World War II.

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Ireland, in the eighteenth century, followed the classic tripartite division of regular medical practitioners into physicians, surgeons and apothecaries. At the beginning of the century surgeons and apothecaries were regarded as mere tradesmen, but by the end of the century both were regarded as professionals and had the right to regulate their respective professions. Practitioners in different regions of Europe developed in a different manner, and eighteenth-century practitioners in Ireland developed independently from their English counterparts. In common with Britain and Europe in the eighteenth century, the total number of practitioners increased in Ireland, and by the end of the century, apothecaries were the largest group in Dublin, closely followed by the surgeons. Surgeons and apothecaries at the start of the eighteenth century belonged to the same guild. However in mid-century, St Luke's guild of apothecaries was established and this provided the apothecaries with a new identity that allowed them to pursue auto regulation, rather than hitherto, when they had been regulated by the physicians. This was vital to the apothecaries as they were in direct commercial competition with both the physicians and the surgeons and faced increasing pressure from both druggists and the disparate group of practitioners known as the irregulars. The 1765 County Infirmaries Act established a hospital in virtually every county in Ireland, and cast the surgeon as the primary medical officer in the countrywide network of hospitals. This legislation, which was unique in Europe, had the unintended consequence of elevating the status of the surgeons, as prior to this physicians were always in the ascendancy in the voluntary hospitals in Ireland and Britain, in contrast to France. The status of the surgeons was further enhanced by the establishment of the College of Surgeons in Ireland in 1784, which provided them with a new corporate identity, the authority to regulate the profession countrywide, and, also, the ability to educate surgeons in Ireland. The establishment of the College of Surgeons placed further pressure on the apothecaries to demonstrate that they also had a recognisable identity, and the authority to regulate their own profession. This was achieved with the 1791 Apothecaries Act which established the Apothecaries Hall and give the apothecaries the right to regulate themselves. This innovative legislation deemed the apothecaries a profession, and was enacted twenty-four years prior to similar legislation in Britain. Commercial pressure from druggists and, probably, irregulars expedited the requirement of the apothecaries to establish a new corporate identity, in order to distance themselves from these groups. The changing status of both apothecaries and surgeons had little effect on the physicians as a group, and, despite being the beneficiaries of a generous bequest from Sir Patrick Dun in 1711 to provide medical chairs in Dublin, the physicians displayed an inertia during the eighteenth century that was not in keeping with the developments that occurred in the contemporary Dublin medical world. The fact that it took ninety-five years, and that five acts of parliament, two House of Commons enquiries and a House of Lords enquiry were required to ensure that Dun's wishes were brought to fruition demonstrates that the physicians did not develop at the same pace as the other medical groups in the city. Had Dun’s bequest been implemented as he desired, Dublin, with a number of voluntary hospitals, would have been well placed to provide comprehensive tuition for medical students in the eighteenth century. It was not until the nineteenth century that the city, and the populace, benefited from this legacy. This thesis will trace these developments in the context of changes that occurred in contemporary medical education and diagnosis in Ireland, Britain and France. It will demonstrate that Irish practitioners developed independently, influenced mainly by local issues, but also by those who had travelled abroad and returned to Ireland with new concepts and ideas, ensuring that Irish medical practitioners had the institutional structure that could encompass the diagnostic and regulatory changes that would become accepted in the nineteenth century.

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Based on Pulay's direct inversion iterative subspace (DIIS) approach, we present a method to accelerate self-consistent field (SCF) convergence. In this method, the quadratic augmented Roothaan-Hall (ARH) energy function, proposed recently by Høst and co-workers [J. Chem. Phys. 129, 124106 (2008)], is used as the object of minimization for obtaining the linear coefficients of Fock matrices within DIIS. This differs from the traditional DIIS of Pulay, which uses an object function derived from the commutator of the density and Fock matrices. Our results show that the present algorithm, abbreviated ADIIS, is more robust and efficient than the energy-DIIS (EDIIS) approach. In particular, several examples demonstrate that the combination of ADIIS and DIIS ("ADIIS+DIIS") is highly reliable and efficient in accelerating SCF convergence.