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61.
Lancaster G.P.T. Häffner H. Wilson M.A. Becher C. Eschner J. Schmidt-Kaler F. Blatt R. 《Applied physics. B, Lasers and optics》2003,76(8):805-808
We present a scheme for employing a violet extended-cavity diode laser in experiments with single, trapped ions. For this the grating-stabilised laser is spatially and spectrally filtered and referenced to a Fabry–Pérot cavity. We measure an upper limit to the line width by observing a 305-kHz FWHM beat note with the second harmonic of a titanium sapphire laser. The laser is subsequently used to optically cool a single 40Ca+ ion close to the Doppler limit. PACS 03.67.Lx; 32.80.Pj; 42.55.Px 相似文献
62.
Huiyun Lin Yi Shen Defu Chen Lisheng Lin Brian C. Wilson Buhong Li Shusen Xie 《Journal of fluorescence》2013,23(1):41-47
The purpose of this study is to investigate the feasibility for quantitative measurement of singlet oxygen (1O2) generation by using a newly developed 1O2-specific fluorescence probe Singlet Oxygen Sensor Green reagent (SOSG). 1O2 generation from photoirradiation of a model photosensitizer Rose Bengal (RB), in initially air-statured phosphate buffered saline (PBS) was indirectly monitored with SOSG. In the presence of 1O2, SOSG can react with 1O2 to produce SOSG endoperoxides (SOSG-EP) that emit strong green fluorescence with the maximum at 531 nm. The green fluorescence of SOSG-EP is mainly dependent on the initial concentrations of RB and SOSG, and the photoirradiation time for 1O2 generation. Furthermore, kinetic analysis of the RB-sensitized photooxidation of SOSG is performed that, for the first time, allows quantitative measurement of 1O2 generation directly from the determination of reaction rate. In addition, the obtained 1O2 quantum yield of porphyrin-based photosensitizer hematoporphyrin monomethyl ether (HMME) in PBS by using SOSG is in good agreement with the value that independently determined by using direct measurement of 1O2 luminescence. The results of this study clearly demonstrate that the quantitative measurement of 1O2 generation using SOSG can be achieved by determining the reaction rate with an appropriate measurement protocol. 相似文献
63.
Alam MS Kim IJ Nemati B O'Neill JJ Romero V Severini H Sun CR Wang P Zoeller MM Crawford G Fulton R Gan KK Kagan H Kass R Lee J Malchow R Morrow F Sung M White C Whitmore J Wilson P Butler F Fu X Kalbfleisch G Lambrecht M Skubic P Snow J Bortoletto D Brown DN Dominick J McIlwain RL Miao T Miller DH Modesitt M Schaffner SF Shibata EI Shipsey IP Battle M Ernst J Kroha H Roberts S Sparks K Thorndike EH Wang C Artuso M Goldberg M Haupt T Horwitz N Kennett R Moneti GC Playfer S Rozen Y Rubin P 《Physical review D: Particles and fields》1992,46(11):4822-4827
64.
S. E. D. Webb S. Lévêque-Fort D. S. Elson J. Siegel T. Watson M. J. Lever M. Booth R. Juskaitis M. A. A. Neil L. O. Sucharov T. Wilson P. M. W. French 《Journal of fluorescence》2002,12(2):279-283
We have developed a compact system for wide-field fluorescence imaging, resolved in three spatial dimensions, lifetime and wavelength, that is based on a gated optical intensifier and an all-solid-state diode pumped Cr:LiSAF oscillator-amplifier system. Exploiting spectral separation, the system has been applied to human teeth, obtaining good lifetime contrast between enamel, dentin and caries. Exploiting spectral separation combined with depth resolution, the study of fluorescent microspheres led to an enhancement in both lifetime contrast and lateral resolution. 相似文献
65.
Akshay Mathkar T. N. Narayanan Lawrence B. Alemany Paris Cox Patrick Nguyen Guanhui Gao Patricia Chang Rebeca Romero‐Aburto Sendurai A. Mani P. M. Ajayan 《Particle & Particle Systems Characterization》2013,30(3):266-272
The richly functionalized basal plane bonded to polar organic moieties makes graphene oxide (GO) innately hydrophilic. Here, a methodology to synthesize fluorinated graphene oxide by oxidizing the basal plane of fluorinated graphite, allowing for tunable hydrophobicity of GO, is reported. Fluorine exists as tertiary alkyl fluorides covalently bonded to graphitic carbons, and using magic‐angle spinning (MAS) 13C NMR as a primary tool chemical structures for the two types of synthesized fluorinated graphene oxides (FGOs) with significantly different fluorine contents are proposed. The low surface energy of the C–F bond drastically affects GO's wetting behavior, leading to amphiphobicity in its highly fluorinated form. Ease of solution processing enables the fabrication of inks that are spray‐painted on various porous/non‐porous substrates. These coatings maintain amphiphobicity for solvents with surface tensions down to 59 dyn/cm, thus bypassing existing lithographic means to create similar surfaces. The approach towards fluorinating GO and fabricating graphene‐based surfaces with tunable wettability opens the path towards unique, accessible, carbon‐based amphiphobic coatings. 相似文献
66.
Samples of Ti–6?wt%?Al–4?wt%?V and Timet 550 (Ti–4?wt%?Al–4?wt%?Mo–2?wt%?Sn–0.5?wt%?Si) have been subjected to strain rates between 10?1 and 103?s?1and detailed examination of the dislocation structure in the α grains has been carried out using transmission electron microscopy (TEM). For samples deformed to a strain of 0.1 at 10?1?s?1, detailed analysis of the defects can be carried out using all diffracting vectors and the presence of (c +?a) dislocations and a dislocations thus confirmed. In contrast, for samples strained to the same strain of 0.1 but at 5?s?1, it is not possible to obtain images of dislocations when using any diffracting vectors other than 0002. Thus the presence of dislocations which have a Burgers vector containing a c component can be confirmed in the samples strained at 5?s?1 but the presence of a-component dislocations can only be inferred from TEM of these samples because of the difficulty of obtaining images with diffracting vectors other than 0002. Limited observations on samples strained at 103?s?1 show that similar difficulties are found in imaging dislocations as are found in samples deformed at 5?s?1 but at this strain rate, the highest used, the difficulties are reduced since images can be obtained in some grains using diffracting vectors other than 0002. These results are discussed in terms of the nature of damage as a function of strain rate and the factors that influence contrast from dislocations in crystals. 相似文献
67.
Validation and generalization of DEA and its uses 总被引:3,自引:0,他引:3
R. D. Banker W. W. Cooper E. Grifell-Tajté Jesús T. Pastor Paul W. Wilson Eduardo Ley C. A. K. Lovell 《TOP》1994,2(2):249-314
Summary Rapidly expanding uses of DEA have been accompanied by developments which have enhanced its power and enlarged its utility
for additional applications. Developments covered in the present paper include simulation studies comparing DEA with competing
forms of statistical regressions. Other studies covered show how these two approaches can be combined in complementary fashion.
Another part of this paper deals with Chance Constrained Programming formulations which incorporate probabilistic elements
into DEA. Included also are discussions of statistical characterizations with accompanying tests of statistical significance
for DEA efficiency evaluations. This paper concludes with uses of DEA in “discovery processes”-processes that need strengthening
(and encouragemnt) in contemporary social science and management science research. Suggestions are made for additional research
on further developments which extend to uses of DEA to provide new approaches in economics (including econometrics), management
and psychology and an Appendix introduces new or recently developed efficiency measures for use in DEA.
Invited by J. T. Pastor 相似文献
68.
The detection, loudness, and discrimination performances of subjects with normal hearing were assessed using 3 five-component tonal complexes (1020-1100 Hz) with crest factors of 1.8, 2.6, and 3.2. The 3 five-component tonal complexes were: (1) equally detectable in broadband noise when presented at equal rms amplitude; (2) perceived as equally loud when presented at essentially equal rms amplitude; and (3) discriminable from one another when presented at equal loudness. The present data indicate that listeners can make discriminations on the basis of amplitude variations. 相似文献
69.
Differential oscillator strengths and dipole polarizabilities for transitions of the helium sequence
The dipole radial integral for an initial discrete 1s state and a final continuum state has been calculated under the screened hydrogenic model. In this model, single-electron hydrogenic wave functions are employed and the initial and the final states are treated by two different effective-charge parameters. Numerical values of differential oscillator strengths for transitions from 1s 21S to the continuum for the helium sequence ions are obtained. Also calculated are the dipole polarizabilities, which are found to be in excellent agreement with the results of other authors. 相似文献
70.
Kim GN Kim EJ Son D Bacala A Imlay R Kirk P McNeil RR Metcalf W Cheng CP Mao ZP Yan Y Xu YT Zhu YC Abashian A Gotow K Kajino F Low E Naito F Piilonen L Childers R Darden C Lusin S Rosenfeld C Wilson S Frautschi M Kagan H Kass R Trahern CG Ko W Lander RL Maeshima K Malchow RL Higashi JR Kurihara Y Maki A Nozaki T Omori T Perez P Sagawa H Sakai Y Sugimoto Y Takaiwa Y Terada S Tsuchiya K Poling R Green J Park IH Sakamoto S Sannes F Schnetzer S Stone R Trentalange S Zimmerman D Miyano K Miyata H 《Physical review letters》1988,61(8):911-914