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101.
Laser-induced acoustic wave generation/propagation/interaction in water in various internal channels
Seung Hwan Ko Daeho Lee Heng Pan Sang-Gil Ryu Costas P. Grigoropoulos Nick Kladias Elias Panides Gerald A. Domoto 《Applied Physics A: Materials Science & Processing》2010,100(2):391-400
Short pulsed laser-induced single acoustic wave generation, propagation, interaction within a water-filled internal channel
are experimentally and numerically studied. A large-area, short-duration, single-plane acoustic wave was generated by the
thermoelastic interaction of a homogenized nanosecond pulsed laser beam with a liquid–solid interface and propagated at the
speed of sound in water. Laser flash Schlieren photography was used to visualize the transient interaction of the plane acoustic
wave in various internal channel structures ((a) sudden expansion and contraction channels, (b) bifurcating channels, (c) gradual
contraction wall channels and (d) a cylinder). Fairly good agreement between the experimental results and numerical simulation
is observed. 相似文献
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Radiolysis of Aqueous Solutions of Benzoate Ion: A Radiation Chemistry Experiment for Undergraduates
This investigation describes the chemical effects of ionizing radiation on dilute aqueous solutions of benzoate ion. We have composed an experimental procedure that allows undergraduate chemistry students to identify and to quantitatively determine the amount of the products that are produced. The student investigators determine the absorbed dose that a sample receives when exposed to a 60Co source, irradiate dilute aqueous solutions of benzoate ion, and analyze the resulting mixture of hydroxybenzoate ions using high-performance liquid chromatography. The radiolysis of dilute solutions of benzoate ion results in the formation of a mixture of ortho-, meta-, and para-hydroxybenzoate ions that are readily separated on a C18 -Bondapak column. By the use of appropriate calibration curves, the yield (G values) of each of the isomers may be determined and compared.This paper was presented at the 15th Biennial Conference on Chemical Education, Waterloo, Ontario, Canada, August 1998 by N. Zevos and at the 26th Northeast Regional Meeting of the American Chemical Society by Evon Powell. 相似文献
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Ballardini R Balzani V Clemente-León M Credi A Gandolfi MT Ishow E Perkins J Stoddart JF Tseng HR Wenger S 《Journal of the American Chemical Society》2002,124(43):12786-12795
We have designed, synthesized, and investigated a self-assembling supramolecular system which mimics, at a molecular level, the function performed by a macroscopic electrical extension cable. The system is made up of three components, 12+, 2-H3+, and 3. Component 12+ consists of two moieties: a [Ru(bpy)3]2+ unit, which plays the role of an electron donor under light excitation, and a DB24C8 crown ether, which fulfills the function of a socket. The wire-type component 2-H3+ is also composed of two moieties, a secondary dialkylammonium-ion center and a bipyridinium unit, which thread into the DB24C8 crown-ether socket of 12+ and the 1/5DN38C10 crown-ether socket 3, respectively. The photochemical, photophysical, and electrochemical properties of the three separated components, of the 12+ superset 2-H3+ and 2-H3+ subset 3 dyads, and of the 12+ superset 2-H3+ subset 3 triad have been investigated in CH2Cl2 solution containing 2% MeCN. Reversible connection/disconnection of the two plug/socket systems can be controlled independently by acid/base and redox stimulation. The behavior of the various different dyads and triad has been monitored by light absorption and emission spectroscopies, as well as by electrochemical techniques. In the fully connected 12+ superset 2-H3+ subset 3 triad, light excitation of the [Ru(bpy)3]2+ unit of component 12+ is followed by electron transfer (k = 2.8 x 108 s-1) to the bipyridinium unit of component 2-H3+, which is plugged into component 3. Possible schemes to obtain improved molecular-level electrical extension cables are discussed. 相似文献