| 1. |
- L'Huillier, Anne, et al.
(författare)
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High-order Harmonics - A Coherent Source In the Xuv Range
- 1995
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Ingår i: Journal of Nonlinear Optical Physics & Materials. - 0218-1991. ; 4:3, s. 647-665
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Tidskriftsartikel (refereegranskat)abstract
- We review the main results concerning high-order generation processes from the point of view of a potential user of this new source of XUV radiation. The perspectives for optimizing the source, both in efficiency and in spectral range, its characteristics and in particular, its coherence properties, are discussed. Finally, we describe two experiments, which demonstrate the usefulness of the harmonics as a short-pulse, coherent source in the XUV domain.
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| 2. |
- Salieres, P, et al.
(författare)
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Angular distributions of high-order harmonics generated by a femtosecond laser
- 1996
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Ingår i: Journal of Physics B: Atomic, Molecular and Optical Physics. - : IOP Publishing. - 0953-4075. ; 29:20, s. 4771-4786
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Tidskriftsartikel (refereegranskat)abstract
- We present a systematic study of the angular distributions of high-order harmonics generated with a femtosecond Cr:LiSrAlF6 laser. We investigate the influence of different parameters, namely laser intensity, nonlinear order, nature of the gas and position of the laser focus relative to the generating medium. We show that when the laser is focused before the atomic medium, harmonics with regular spatial profiles can be generated with reasonable conversion efficiency. Their divergence does not depend directly on the nonlinear order, the intensity or even the nature of the generating gas, but rather on the region of the spectrum the considered harmonic belongs to, which is determined by the combination of the three preceding elements. When the focus is drawn closer to the medium, the distributions get increasingly distorted, becoming annular with a significant divergence for a focus right into-or after-the jet. We perform numerical simulations of the angular distributions. The simulated profiles reproduce remarkably well the experimental trends and are thus used to interpret them.
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| 3. |
- Saunders, Carol D., et al.
(författare)
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Summative Evaluation of "The Swamp": : A Conservation Exhibit with a Big Idea
- 1997
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Ingår i: Visitor Behavior. - Jacksonville, FL, USA. - 0892-4996. ; XII:1 & 2, s. 4-7
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Tidskriftsartikel (refereegranskat)abstract
- In this article, Carol D. Saunders and H. Elizabeth Stuart Perry of the Brookfield Zoo provide findings from the summative evaluation of "The Swamp." This immersive wetlands exhibit was designed to encourage people to appreciate the benefits of ecosystems and features animals and plants of a cypress swamp and of an Illinois riverine wetland.
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| 4. |
- Stuart Perry, H. Elizabeth, 1975-, et al.
(författare)
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Integrating Evaluation in to a Technology Education Program
- 1997
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Ingår i: Visitor Studies. - Jacksonville, AL, USA : The Visitor Studies Association. - 1064-5578 .- 1934-7715. ; 9:1, s. 247-257
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Tidskriftsartikel (refereegranskat)abstract
- Most, if not all, states in this country have school districts and boards of education interested in the uses of technologies for education at the K¥12 and higher education levels. Technologies in use and under consideration range from CD-ROMs and digital cameras to desktop networked computers with access to the resources of the Internet and the World Wide Web (NCREL, 1995). Well-planned technology programs in schools have the obvious benefit of teaching young people in a technological age to be comfortable and proficient with technologies. Being connected to the Internet also offers students a window to real¥world, up-to-the-minute information, which can improve learning. But how do we determine the success of such programs? This paper presents a case study in evaluating a technology project involving partnerships between museums and formal education. The focus is on multi-method design.
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