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31.
32.
M.J. Dick P.M. Sheridan J.-G. Wang S. Yu P.F. Bernath 《Journal of Molecular Spectroscopy》2006,240(2):238-243
The state of CaOH was investigated using optical–optical double resonance spectroscopy. A combined least-squares fit of the double resonance transition data along with optical transition data and the millimeter-wave pure rotational data of the state was performed using an effective Hamiltonian. The spin–rotation constant was determined for the state for the first time. An analysis of these constants showed that the Ca–O bond length and spin–rotation parameter of the state have the smallest values of all the observed 2Σ+ states of CaOH. This evidence suggests the assignment of the state as arising from a Ca+ atomic orbital of mainly 5sσ character. This atomic orbital assignment was shown to be consistent with both previous work on CaF and recent theoretical calculations on CaOH. 相似文献
33.
Synchrotron X‐ray CT characterization of titanium parts fabricated by additive manufacturing. Part I. Morphology 下载免费PDF全文
Nicola Vivienne Yorke Scarlett Peter Tyson Darren Fraser Sheridan Mayo Anton Maksimenko 《Journal of synchrotron radiation》2016,23(4):1006-1014
Synchrotron X‐ray tomography has been applied to the study of titanium parts fabricated by additive manufacturing (AM). The AM method employed here was the Arcam EBM® (electron beam melting) process which uses powdered titanium alloy, Ti64 (Ti alloy with approximately 6%Al and 4%V), as the feed and an electron beam for the sintering/welding. The experiment was conducted on the Imaging and Medical Beamline of the Australian Synchrotron. Samples were chosen to examine the effect of build direction and complexity of design on the surface morphology and final dimensions of the piece. 相似文献
34.
Degao Wang Zihao Xu Matthew V. Sheridan Javier J. Concepcion Fei Li Tianquan Lian Thomas J. Meyer 《Chemical science》2021,12(43):14441
In photosynthesis, solar energy is used to produce solar fuels in the form of new chemical bonds. A critical step to mimic photosystem II (PS II), a key protein in nature''s photosynthesis, for artificial photosynthesis is designing devices for efficient light-driven water oxidation. Here, we describe a single molecular assembly electrode that duplicates the key components of PSII. It consists of a polypyridyl light absorber, chemically linked to an intermediate electron donor, with a molecular-based water oxidation catalyst on a SnO2/TiO2 core/shell electrode. The synthetic device mimics PSII in achieving sustained, light-driven water oxidation catalysis. It highlights the value of the tyrosine–histidine pair in PSII in achieving efficient water oxidation catalysis in artificial photosynthetic devices.We describe a single molecular assembly electrode that mimics PSII. Flash photolysis revealed the electron transfer steps between chromophore light absorption and the creation and storage of redox equivalents in the catalyst for water oxidation. 相似文献
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36.
Analysis of phase encoding for optical encryption 总被引:1,自引:0,他引:1
David S. Monaghan Guohai Situ Thomas J. Naughton John T. Sheridan 《Optics Communications》2009,282(4):482-750
A phase encoded image is encrypted using the double random phase encoding technique, (DRPE). The effects of using a variable dynamic range of phase distribution during phase encoding (pre-encryption) are examined. We begin by phase encoding the input image using the full phase range, from −π to π. We perform numerically perfect encryption and we then introduce errors into the decrypting phase-keys in the form of a pseudo-random distribution (position and phase) of incorrect pixels values. By quantifying the resulting error in the attempted decryptions, for increasing amounts of error in the decrypting phase-keys, we examine the effects of reducing the phase range to, +/− (π − Δ). In this way we attempt to improve the phase encoding procedure for use with the DRPE technique. When the pixel values calculated, during an attempted decryption, fall outside the phase range used to phase encode the assigned input image, we examine different methods of redistributing the value of that pixel to an assigned value within the allowed phase range. The effects of the phase quantisation used in the keys are also examined. 相似文献
37.
Jonathan T. Smith Janice Ward James A. Guthrie Maria B. Sheridan Sheila Boyes Daniel Wilson Judy I. Wyatt Darren Treanor Philip J. Robinson 《Magnetic resonance imaging》2012
Objective
Chemotherapy commonly causes liver injury through sinusoidal obstructive syndrome and steatosis. Chemotherapy-induced liver injury may make it more difficult to detect metastases secondary to reduced contrast between the injured liver and metastases. The aim of this study was to determine the sensitivity of superparamagnetic iron oxide (SPIO) contrast-enhanced imaging in patients who have undergone chemotherapy prior to liver surgery.Methods
Local ethics committee approval was obtained. Thirty-one patients with hepatic metastases completing preoperative chemotherapy were prospectively recruited. Images were reviewed independently by two blinded observers who identified and localized lesions with a four-point confidence scale. The alternative free-response receiver operator characteristic method was used to analyze the results.Results
The sensitivity in detecting colorectal metastases following chemotherapy was 78% and 76%, respectively, for observers 1 and 2 (95% confidence interval: 71%–85% and 68%–82%). The areas under the alternative free-response receiver operator curves were 0.73 and 0.80 for observers 1 and 2, respectively.Conclusion
Compared to previously published work on chemotherapy-naïve patients, it is clear that the sensitivity of SPIO-enhanced magnetic resonance imaging (MRI) in detecting colorectal metastases following chemotherapy is reduced. It is therefore critical that all imaging — pre-, during and postchemotherapy — is reviewed when reporting liver MRI prior to surgery. 相似文献38.
Computer simulations based on Discrete Element Method have been performed in order to investigate the influence of interparticle interactions on the kinetics of self-assembly and the mechanical strength of nanoparticle aggregates.Three different systems have been considered.In the first system the interaction between particles has been simulated using the JKR (Johnson,Kendall and Roberts) contact theory,while in the second and third systems the interaction between particles has been simulated using van der Waals and electrostatic forces respectively.In order to compare the mechanical behaviour of the three systems,the magnitude of the maximum attractive force between particles has been kept the same in all cases.However,the relationship between force and separation distance differs from case to case and thus,the range of the interparticle force.The results clearly indicate that as the range of the interparticle force increases,the self-assembly process is faster and the work required to produce the mechanical failure of the assemblies increases by more than one order of magnitude. 相似文献
39.
Photopolymer holographic recording material 总被引:1,自引:0,他引:1
40.
WITHDRAWN TO APPEAR IN SPECIAL ISSUE IN 2007 相似文献