131,092 research outputs found
Laser Interference Structuring Of A-gen For The Production Of Optical Diffraction Gratings
No full textIn this work, we study the pulsed laser crystallization of hydrogen-free amorphous germanium-nitrogen alloys (a-GeN). We discuss the role of nitrogen during phase transitions and the possible application of the resulting structure as an optical diffraction grating. The crystallized region results of pure microcrystalline germanium (μc-Ge). An indication that Ge-N bonds have broken and nitrogen outdiffused of the film is obtained from infrared spectroscopy and confirmed by Raman spectra. A pattern of alternating a-GeN and μc-Ge lines with a period of about 4 μm acts as an optical diffraction grating due to the difference in optical properties between the two materials, and the three dimensional surface profile, caused by N2 effusion, that is formed on the sample.762717722Lin, C.W., Tseng, C.H., Chang, T.K., Lin, C.W., Wang, W.T., Cheng, H.C., (2002) IEEE Electron Device Letters, 23, p. 133Hatanaka, Y., Niraula, M., Nakamura, A., Aoki, T., (2001) Applied Surface Science, 175, p. 462Toet, D., Smith, P.M., Sigmon, T.W., Thompson, M.O., (2000) Applied Physics Letters, 77, p. 307Lu, J.P., Mei, P., Fulks, R.T., Rahn, J., Ho, J., Wang, Y., Boyce, J.B., Street, R.A., (2000) Journal of Vaccum Science and Technology A- Vacuum Surfaces and Films, 18, p. 1823Sposili, R.S., Im, J.S., (1998) Applied Physics A- Materials Science and Processing, 67, p. 273Im, J.S., Sposili, R.S., Crowder, M.A., (1997) Applied Physics Letters, 70, p. 3434Sposili, R.S., Im, J.S., (1996) Applied Physics Letters, 69, p. 2864Sameshima, T., (1996) Applied Surface Science, 96 (8), p. 352Gosain, D.P., Machida, A., Usui, S., Arai, M., (2001) Polycrystalline Semiconductors IV Materials, Technologies and Large Area Electronics, 80-81, p. 169Gosain, D.P., Noguchi, T., Usui, S., (2000) Japanese Journal of Applied Physics Part 2 - Letters, 39, pp. L179Carey, P.G., Smith, P.M., Theiss, S.D., Wickboldt, P., (1999) Journal of Vacuum Science and Technology A - Vacuum Surfaces and Films, 17, p. 1946Mulato, M., Toet, D., Aichmayr, G., Santos, P.V., Chambouleyron, I., (1997) Appl. Phys. Lett., 70, p. 3570Aichmayr, G., Toet, D., Mulato, M., Santos, P.V., Spangenberg, A., Christiansen, S., Albrecht, M., Strunk, H.P., (1998) Phys. Stat. Sol. (a), 166, p. 659Aichmayr, G., Toet, D., Mulato, M., Santos, P.V., Spangenberg, A., Bergman, R.B., (1998) J. of Non-cryst. Solids, 227-230, p. 921Mulato, M., Toet, D., Aichmayr, G., Spangenberg, A., Santos, P.V., Chambouleyron, I., (1998) J. of Non-cryst. Solids, 227-230, p. 930Aichmayr, G., Toet, D., Mulato, M., Santos, P.V., Spangenberg, A., Christiansen, S., Albrecht, M., (1999) J. Appl. Phys., 85, p. 4010Gupta, V.V., Song, H.J., Im, J.S., (1997) Applied Physics Letters, 71, p. 99Heintze, M., Santos, P.V., Nebel, C.E., Stutzmann, M., (1994) Appl Phys. Lett., 64, p. 3148Mulato, M., Toet, D., Aichmayr, G., Santos, P.V., Chambouleyron, I., (1997) J. Appl. Phys., 82, p. 5159Zanatta, A.R., Chambouleyron, I., (1993) Phys. Rev. B, 48, p. 4560Swanepoel, R., (1983) J. Phys. E: Sci Instrum, 16, p. 1214Marques, F.C., Chambouleyron, I., Evangelisti, F., (1989) J. of Non-cryst. Solids, 114, p. 561Guanchua, C., Fangqing, Z., (1990) This Solid Films, 185, p. 231Marques, F.C., Lacerda, R.G., Lima Jr., M.M., Vilcarromero, J., (1995) Phys. Stat. Sol(b), 192, p. 549Zanatta, A.R., Chambouleyron, I., Santos, P.V., (1996) J. Appl. Phys., 79, p.
Short-pulse Laser Crystallization And Structuring Of A-ge
No full textLaser pulses in the nanosecond range were used to crystallize and structure (lateral dimensions ≤ 1 μm) amorphous germanium thin films. The crystallized material consists of grains with sizes increasing from about 5 to more than 20 nm as a function of laser pulse energy. Arrays of polycrystalline Ge dots (diameter ∼ 1 μm, period ∼ 5 μm) were produced by bringing three laser beams to interference on the sample surface. These arrays can be used as seeds for solid-phase growth of polycrystalline areas by thermal annealing below 450°C. © 1998 Elsevier Science B.V. All rights reserved.227-230PART 2930933Heintze, M., Santos, P.V., Nebel, C.E., Stutzmann, M., (1994) Appl. Phys. Lett., 64, p. 3148Chapman, R.L., Fan, J.C.C., Zeiger, H.J., Gale, R.P., (1980) Appl. Phys. Lett., 37, p. 292Césari, C., Nihoul, G., Marfaing, J., Marine, W., Mutaftschiev, B., (1985) Surf. Sci., 162, p. 724Sharma, R.K., Bansal, S.K., Nath, R., Srivastava, G.P., (1982) Thin Solid Films, 97, p. 1Mulato, M., Toet, D., Aichmayr, G., Santos, P.V., Chambouleyron, I., (1997) Appl. Phys. Lett., 70, p. 3570Mulato, M., Toet, D., Aichmayr, G., Santos, P.V., Chambouleyron, I., in printToet, D., Koopmans, B., Richards, B., Santos, P.V., Bergman, R., (1996) Proc. of the 23rd ICPS, p. 1123. , M. Sheffer, R. Zimermann (Eds.), World Scientific, SingaporeJellison G.E., Jr., Lowndes, D.H., (1987) Appl. Phys. Lett., 51, p. 352Anastassakis, E., Liarokapis, E., (1987) J. Appl. Phys., 62, p. 3346Campbell, I.H., Fauchet, P.M., (1986) Solid State Commun., 58, p. 739Richter, H., Wang, Z.P., Ley, L., (1981) Solid State Commun., 39, p. 62
MeSH term explosion and author rank improve expert recommendations
No full textInformation overload is an often-cited phenomenon that reduces the productivity, efficiency and efficacy of scientists. One challenge for scientists is to find appropriate collaborators in their research. The literature describes various solutions to the problem of expertise location, but most current approaches do not appear to be very suitable for expert recommendations in biomedical research. In this study, we present the development and initial evaluation of a vector space model-based algorithm to calculate researcher similarity using four inputs: 1) MeSH terms of publications; 2) MeSH terms and author rank; 3) exploded MeSH terms; and 4) exploded MeSH terms and author rank. We developed and evaluated the algorithm using a data set of 17,525 authors and their 22,542 papers. On average, our algorithms correctly predicted 2.5 of the top 5/10 coauthors of individual scientists. Exploded MeSH and author rank outperformed all other algorithms in accuracy, followed closely by MeSH and author rank. Our results show that the accuracy of MeSH term-based matching can be enhanced with other metadata such as author rank
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
Ground effect aerodynamics of racing cars
No full textWe review the progress made during the last thirty years on ground effect aerodynamics associated with race cars, in particular open wheel race cars. Ground effect aerodynamics of race cars is concerned with generating downforce, principally via low pressure on the surfaces nearest to the ground. The “ground effected” parts of an open wheeled car's aerodynamics are the most aerodynamically efficient and contribute less drag than that associated with, for example, an upper rear wing. Whilst drag reduction is an important part of the research, downforce generation plays a greater role in lap time reduction. Aerodynamics plays a vital role in determining speed and acceleration (including longitudinal acceleration but principally cornering acceleration), thus performance. Attention is paid to wings and diffusers in ground effect and wheel aerodynamics. For the wings and diffusers in ground effect, major physical features are identified and force regimes classified, including the phenomena of downforce enhancement, maximum downforce and downforce reduction. In particular the role played by force enhancement edge vortices is demonstrated. Apart from model tests, advances and problems in numerical modeling of ground effect aerodynamics are also reviewed and discussed
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Scholarly Communication and Publishing Lunch and Learn Talk #11: The ULS Open Access Author Fee Fund
No full textAt the May 2014 talk, you will learn about the ULS Open Access Author Fee Fund--what it is, why we do it, how it works, and how the program is going so far
Evaluation of a color fused dual-band NVG
No full textWe have tested a prototype dual-band NVG system consisting of two NVGs fitted with filters that split the NVG sensitive range into a short (visual) and a long wavelength (NIR) band. The Color-the-night technique (see Hogervorst & Toet, SPIE D&S ‘08) was used to fuse the images of the two sensors. We designed a color scheme especially optimized for the detection of camouflaged targets. The added value of this system was evaluated in an experiment in which observers had to detect targets (green and blue tubes). Daytime images were taken with a normal camera, and NVG images were recorded at night. Performance was tested for i) the visual band only, ii) the NIR-band only, iii) normal NVG, iv) daytime imagery and v) color fused dual-band NVG. The results show that some targets were detected in the individual bands, but most targets were detected in the dual-band system, with performance comparable to that of the band optimally presenting that particular target. Our evaluation shows the added value of dual-band over single band NVG for the detection of targets, and suggests better situational awareness and perceived depth
- …
