988 resultados para II-VI semiconductor


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Mode of access: Internet.

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Contiene: T. I : Continens pontificatus Clementis XIII. Annum primum, et secundum (1835. XXVIII, 411 p.) -- T. II : Annum tertium ad sextum (1837. XXII, 550 p.) -- T. III : Clementis XIII. Septimum ad undecimum (1838. XXII, 591 p.) -- T. IV : Clementis XIV. Primum ad sextum (1841. XXVII, 806 p.) -- T. V : Pii VI. Annum primum ad tertium (1842. XIX, 490 p.) -- T. VI : Quartum ad octavum (1843. XXIV, 626 p.) -- T. VII : Annum nonum ad duodecimum (1843. XVII, 714 p.) -- T. VIII : Pii VI, [annum] XIII ad XVI (1844. XVII, 574 p.) -- T. IX : Annum decimum septimum ad vicesimum primum (1845. XXI, 638 p.) -- T. X: Vicesimum secundum ad vicesimum quintum (1845. XVIII, 250 p.) -- T. XI: Pii VII. Annum primum ad tertium (1846. XXI, 510 p.) -- T. XII : Pii VII. Annum quartum ad sextum (1846. XXI, 450 p.) -- T. XIII : Septimum ad sextum decimum (1847. XXIII, 488 p.) -- T. XIV: Annum decimum septimum ad octavum (1849. XII, 626 p.) -- T. XV: Annum decimum nonum ad vicesimum quartum (1853. XXIV, 650 p.) -- T. XVI: Leonis XII. Annum primum ad tertium (1854. XV, 490 p.) -- T. XVII: Annum quartum ad sextum (1855. XV, 483 p.) -- T. XVIII: Pii VIII. Annum primum et secundum (1856. XV, 168 p.) -- T. XIX: Gregorii XVI. Annum primum ad quartum (1857. XXVI, 714 p.) -- T. XX: Gregorii XVI. Annum quintum (1858)

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"Sacra Christi Pentacostalia : pie riteque celebranda Academiae Fridericianae Halis Consociatae : civibus indicit prorector cum directore et seantu : inest Commentatio de vi quam graeca philosophia in theologiam tum Muhammedanorum tum Iudaeorum exercuerit."

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"Les lamentacions et les épistres de Pierre Salmon": p.[41]-167.

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On spine: Hearne's Ann. Edvardi II, 1729.

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t. I. Varia scripta ad historiam et ivs pvblicvm Imperii germanici ... spectantia ... cvm praefatione et vita Conringii.--t. II. Varia scripta ad historiam, prvdentiam civilem, et ivs pvblicvm Umperii romano-germanici spectantia.--t. III. Continens varia scripta politica, inprimis

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no. I. On the cultivation of children, in the spirit of Pestalozzi's method. 5th ed. 1827.--no. II. Exercises for exciting the attention and strengthening the thinking powers of children ... 5th ed. 1829.--no. III. First exercises in number; or, The elements of arithmetic visibly represented ... 4th ed. 1829.--no. IV. First exercises in forms. Intuition and denomination of the most simple relations of forms, their position and magnitude ... 2d ed. 1827.--no. V. First exercises in language ... 2d ed. 1827.--no. VI. Religious conversations, calculated for young children during the first period of education ... 1827.

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Thesis (Ph.D.)--University of Washington, 2016-06

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The focusing of multimode laser diode beams is probably the most significant problem that hinders the expansion of the high-power semiconductor lasers in many spatially-demanding applications. Generally, the 'quality' of laser beams is characterized by so-called 'beam propagation parameter' M2, which is defined as the ratio of the divergence of the laser beam to that of a diffraction-limited counterpart. Therefore, M2 determines the ratio of the beam focal-spot size to that of the 'ideal' Gaussian beam focused by the same optical system. Typically, M2 takes the value of 20-50 for high-power broad-stripe laser diodes thus making the focal-spot 1-2 orders of magnitude larger than the diffraction limit. The idea of 'superfocusing' for high-M2 beams relies on a technique developed for the generation of Bessel beams from laser diodes using a cone-shaped lens (axicon). With traditional focusing of multimode radiation, different curvatures of the wavefronts of the various constituent modes lead to a shift of their focal points along the optical axis that in turn implies larger focal-spot sizes with correspondingly increased values of M2. In contrast, the generation of a Bessel-type beam with an axicon relies on 'self-interference' of each mode thus eliminating the underlying reason for an increase in the focal-spot size. For an experimental demonstration of the proposed technique, we used a fiber-coupled laser diode with M2 below 20 and an emission wavelength in ~1μm range. Utilization of the axicons with apex angle of 140deg, made by direct laser writing on a fiber tip, enabled the demonstration of an order of magnitude decrease of the focal-spot size compared to that achievable using an 'ideal' lens of unity numerical aperture. © 2014 SPIE.

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A diode-cladding-pumped mid-infrared passively Q-switched Ho 3+-doped fluoride fiber laser using a reverse designed broad band semiconductor saturable mirror (SESAM) was demonstrated. Nonlinear reflectivity of the SESAM was measured using an in-house Yb3+-doped mode-locked fiber laser at 1062 nm. Stable pulse train was produced at a slope efficient of 12.1% with respect to the launched pump power. Maximum pulse energy of 6.65 μJ with a pulse width of 1.68 μs and signal to noise ratio (SNR) of ~50 dB was achieved at a repetition rate of 47.6 kHz and center wavelength of 2.971 μm. To the best of our knowledge, this is the first 3 μm region SESAM based Q-switched fiber laser with the highest average power and pulse energy, as well as the longest wavelength from mid-infrared passively Q-switched fluoride fiber lasers. © 2014 SPIE.

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In the United States, public school enrollment is typically organized by neighborhood boundaries. This dissertation examines whether the federally funded HOPE VI program influenced performance in neighborhood public schools. In effect since 1992, HOPE VI has sought to revitalize distressed public housing using the New Urbanism model of mixed income communities. There are 165 such HOPE VI projects nationwide. Despite nearly two decades of the program's implementation, the literature on its connection to public school performance is thin. My dissertation aims to narrow this research gap. There are three principal research questions: (1) Following HOPE VI, was there a change in socioeconomic status (SES) in the neighborhood public school? The hypothesis is that low SES (measured as the proportion of students qualifying for the Free and Reduced Lunch Program) would reduce. (2) Following HOPE VI, did the performance of neighborhood public schools change? The hypothesis is that the school performance, measured by the proportion of 5th grade students proficient in state wide math and reading tests, would increase. (3) What factors relate to the performance of public schools in HOPE VI communities? The focus is on non-school, neighborhood factors that influence the public school performance. For answering the first two questions, I used t-tests and regression models to test the hypotheses. The analysis shows that there is no statistically significant change in SES following HOPE VI. However, there are statistically significant increases in performance for reading and math proficiency. The results are interesting in indicating that HOPE VI neighborhood improvement may have some relationship with improving school performance. To answer the third question, I conducted a case study analysis of two HOPE VI neighborhood public schools, one which improved significantly (in Philadelphia) and one which declined the most (in Washington DC). The analysis revealed three insights into neighborhood factors for improved school performance: (i) a strong local community organization; (ii) local community's commitment (including the middle income families) to send children to the public school; and (iii) ties between housing and education officials to implement the federal housing program. In essence, the study reveals how housing policy is de facto education policy.