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991.
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Ping Hei Ronnie Ng Sarah Walker Mark Tahtouh Brian Reedy 《Analytical and bioanalytical chemistry》2009,394(8):2039-2048
FTIR and Raman spectral imaging can be used to simultaneously image a latent fingerprint and detect exogenous substances deposited
within it. These substances might include drugs of abuse or traces of explosives or gunshot residue. In this work, spectral
searching algorithms were tested for their efficacy in finding targeted substances deposited within fingerprints. “Reverse”
library searching, where a large number of possibly poor-quality spectra from a spectral image are searched against a small
number of high-quality reference spectra, poses problems for common search algorithms as they are usually implemented. Out
of a range of algorithms which included conventional Euclidean distance searching, the spectral angle mapper (SAM) and correlation
algorithms gave the best results when used with second-derivative image and reference spectra. All methods tested gave poorer
performances with first derivative and undifferentiated spectra. In a search against a caffeine reference, the SAM and correlation
methods were able to correctly rank a set of 40 confirmed but poor-quality caffeine spectra at the top of a dataset which
also contained 4,096 spectra from an image of an uncontaminated latent fingerprint. These methods also successfully and individually
detected aspirin, diazepam and caffeine that had been deposited together in another fingerprint, and they did not indicate
any of these substances as a match in a search for another substance which was known not to be present. The SAM was used to
successfully locate explosive components in fingerprints deposited on silicon windows. The potential of other spectral searching
algorithms used in the field of remote sensing is considered, and the applicability of the methods tested in this work to
other modes of spectral imaging is discussed. 相似文献
994.
995.
Di Wei Steve J. Wakeham Tin Wing Ng Mike J. Thwaites Hayley Brown Paul Beecher 《Electrochemistry communications》2009,11(12):2285-2287
This paper describes a novel strategy to make fully transparent, solid-state and flexible supercapacitors based on room temperature ionic liquid (RTIL) gel and ITO electrodes coated on transparent polymer substrate without a separator, which enables the roll-to-roll technique for fabrication of such supercapacitors as printable devices. This is the first type of transparent electrochemical double layer capacitor (EDLC) based on ionic liquid gel. 相似文献
996.
Synthesis and characterization of soluble conjugated polymers having pyrene moiety in the main chain
Hui Chen Xiao Hu Siu‐Choon Ng 《Journal of polymer science. Part A, Polymer chemistry》2010,48(23):5562-5569
Three new alternating conjugated polymers consisting of pyrene and 3‐dodecylthiophene ( PPyMT ), 4,4′‐didodecyl‐2,2′‐bithiophene ( PPyBT ), or 9,9‐didodecylfluorene ( PPyFlu ) moieties have been prepared using Suzuki coupling reaction or Sugimoto approaches. The polymers were readily soluble in common organic solvents and exhibited good thermal stability in nitrogen and air atmospheres. The structures and optical properties of the polymers were characterized by NMR, FTIR, XRD, UV–vis, and fluorescence spectroscopy. PPyMT and PPYBT showed blue‐light emission in solution, whereas PPyFlu performed blue‐light emitting in film state. The polymers exhibited an intermolecular aggregation and structural ordering due to pyrene–pyrene π–π stacking interaction. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010 相似文献
997.
We consider the problem of scheduling multi-operation jobs on a singe machine to minimize the total completion time. Each job consists of several operations that belong to different families. In a schedule each family of job operations may be processed as batches with each batch incurring a set-up time. A job is completed when all of its operations have been processed. We first show that the problem is strongly NP-hard even when the set-up times are common and each operation is not missing. When the operations have identical processing times and either the maximum set-up time is sufficiently small or the minimum set-up time is sufficiently large, the problem can be solved in polynomial time. We then consider the problem under the job-batch restriction in which the operations of each batch is partitioned into operation batches according to a partition of the jobs. We show that this case of the problem can be solved in polynomial time under a certain condition. 相似文献
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999.
In this study, detonation cell sizes of methanol–oxygen mixtures are experimentally measured at different initial pressures
and compositions. Good agreement is found between the experiment data and predictions based on the chemical length scales
obtained from a detailed chemical kinetic model. To assess the detonation sensitivity in methanol–oxygen mixtures, the results
are compared with those of hydrogen–oxygen and methane–oxygen mixtures. Based on the cell size comparison, it is shown that
methanol–oxygen is more detonation sensitive than methane–oxygen but less sensitive than hydrogen–oxygen. 相似文献
1000.