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31.
Yu. I. Latyshev A. V. Frolov V. A. Volkov T. Wade V. A. Prudkoglyad A. P. Orlov V. M. Pudalov M. Konczykowski 《JETP Letters》2018,107(3):192-195
The longitudinal magnetoresistance of the array of parallel-oriented bismuth nanowires each 100 nm in diameter grown by electrochemical deposition in nanopores of an Al2O3 membrane has been studied in magnetic fields up to 14 T and at temperatures down to 0.3 K. The resistance increases with the field and reaches a broad maximum in fields about 10 T. An anomalous increase in the resistance in weak fields is qualitatively consistent with the suppression of the antilocalization correction to the resistance, and the maximum is qualitatively associated with the classical size effect. Near the maximum at temperatures below 0.8 K, manifestations of reproducible magneto-oscillations of the resistance, which are periodic in field, have been detected. The period of these oscillations is close to a value corresponding to the passage of the flux quantum hc/e through the section of a nanowire. The Fourier analysis also confirms that the oscillations are periodic. This result is similar to the manifestation the Aharonov–Bohm effect caused by conducting surface states of Dirac fermions occupying L-valleys of bismuth. 相似文献
32.
Atomic force microscopy (AFM) was used to assess the indentation modulus M s and pull-off force F po in four case studies of distinct evidence types, namely hair, questioned documents, fingerprints, and explosive particle-surface interactions. In the hair study, M s decreased and F po increased after adding conditioner and bleach to the hair. For the questioned documents, M s and F po of two inks were markedly different; ballpoint pen ink exhibited smaller variations relative to the mean value than printer ink. The fingerprint case study revealed that both maximum height and F po decreased over a three-day period. Finally, the study on explosive particle-surface interactions illustrated that two fabrics exhibited similar M s, but different F po. Overall, it was found that AFM addresses needs in forensic science as defined by several federal agencies, in particular an improved ability to expand the information extracted from evidence and to quantify its evidentiary value. 相似文献
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W. H. Cook E. P. Griffing und C. L. Alsberg 《Fresenius' Journal of Analytical Chemistry》1933,91(5-6):195
Ohne Zusammenfassung 相似文献
36.
Yohann Catel Michel Degrange Loïc Le Pluart Pierre‐Jean Madec Thi‐Nhàn Pham Fei Chen Wayne D. Cook 《Journal of polymer science. Part A, Polymer chemistry》2009,47(20):5258-5271
Four new monomers, 3‐(N‐methylacrylamido)propylidenebisphosphonic acid, 3‐(N‐propyl‐acrylamido)propylidenebisphosphonic acid, 3‐(N‐hexylacrylamido)propylidenebisphosphonic acid, and 3‐(N‐octylacrylamido)propylidenebisphosphonic acid, have been synthesized in good yields and fully characterized by 1H, 13C, 31P NMR, and HRMS. The copolymerization of these monomers with N,N′‐diethyl‐1,3‐bis(acrylamido)propane (DEBAAP) has been investigated with differential scanning calorimetry. These mixtures show a higher reactivity than DEBAAP. New self‐etch dental primers, based on these acrylamide monomers, have been formulated. Dentin shear bond strength measurements have shown that primers based on these bisphosphonic acids assure a strong bond between the tooth substance and a dental composite. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5258–5271, 2009 相似文献
37.
A new National Science Foundation supported curriculum, Interactions in Physical Science?, was evaluated on students’ conceptual change in the twelve concept areas of the national physical science content standard (B) for grades 5–8. Eighth grade students (N=66) were evaluated pre and post on a 31‐item multiple‐choice test of conceptual understanding developed by the Harvard ‐Smithsonian Center for Astrophysics. Significant student gains (p<. 05, t‐test, two‐tailed) occurred in all concept areas in the category of properties and changes in properties of matter; for the force concept areas in the category motions and forces; and for the heat transfer and light interactions areas in the category of transfer of energy. Two of the six concept areas in the category of transfer of energy, chemical and nuclear reactions and the sun as a major source of energy, were not addressed in this study. Significant learning gains as item percent correct were typically close to 20%, though effect sizes were small to medium in magnitude (d = 0.3–0.6). Implications of the study for conceptual change curriculum and teaching are discussed. 相似文献
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J. Terrier D. H. Cook J. H. Axtmayer Ira E. Puddington J. F. Snell und J. L. Perlman 《Fresenius' Journal of Analytical Chemistry》1939,117(5-6):223-225
Ohne Zusammenfassung 相似文献
40.
M. W. Raynor G. F. Shilstone K. D. Bartle A. A. Clifford M. Cleary B. W. Cook 《Journal of separation science》1989,12(5):300-302
Xenon is investigated as a mobile phase for on-line capillary supercritical fluid chromatography-Fourier transform infrared spectrometry (SFC-FTIR). Polycyclic aromatic hydrocarbons, aromatic isocyanates, and epoxy acrylate oligomers are analyzed as examples to show that xenon has similar selectivities and solvating powe to CO2. Its optical transparency makes it ideal for IR detection. A stop flow system is constructed to increase the sensitivity of spectra measured from compounds which are weak IR absorbers. 相似文献