Streaming Molecular

Haab B B and Mathies R A 1999 Single-molecule detection of DNA separations in microfabricated capillary electrophoresis chips employing focused molecular streams Ana/. Chem. 71 5137-45... 

Lewis s "decision" between rival theories was published in the paper written with Joseph E. Mayer, "A Disproof of the Radiation Theory of Chemical Activation," Proc.NAS 13 (1927) 623625. A copy of the news release is in the College of Chemistry Papers, 19231936, BL.UCB. Lewis wrote A. F. Joffe in fall 1927 of Mayer s failure to find a chemical reaction when a molecular stream is passed through a radiation field. Letter from G. N. Lewis to A. F. Joffe, 27 October 1927, Lewis Papers, BL.UCL. 

We, therefore, decided to study the reaction of a molecular stream passing through an exhausted enclosure which is permeated by radiation corresponding to a temperature that would be sufficient under ordinary circumstances to produce chemical reaction. Since, in the molecular stream, the gas is at so low a concentration that the mean free path is considerably longer than the length of the stream, the number of collision is negligible. This method seems, therefore, to offer a direct means of investigating the reaction due to radiation alone. 

Since we planned to collect on a receiving surface the material passing straight through the molecular stream, and to ascertain from analysis of this portion the fraction reacting, it seemed inexpedient to employ nitrogen pentoxide or any other sul tance which dissociates into two or... 

If the entry tube to the gauge is too narrow (and/or long), the statistical movement of molecules to enter the gauge may be inaccurately low. On the other hand if the angle of the tube to the gauge is in direct line with a molecular stream, the count of molecules could be inaccurately high. 

Carman P. C., Diffusion and flow of gases and vapours through micropores I. Slip flow and molecular streaming. Proc.Roy.Soc.(London) A203 (1950) pp. 55-74. 

Its pathway is complete. At one end of the pulsing, spiraling avenue is the mountain. At the other end is myself. This molecular stream is the energy that flows between us. There is nothing for me to do now but to stand and appreciate. I had thought, I had hoped, that my walk would lead me to the mountain. This stream of violet light is happening outside of my hopes. My walk has led me toward the mountain, but the mountain has also come to me. 

Haab, B.B. and Mathies, R.A., Single-molecule detection of DNA separations in microfabricated capillary electrophoresis chips employing focused molecular streams. Anal. Chem., 71,5137, 1999. Jacobson, S.C., Hergenrdder, R., Koutny, L.B., Warmack, R.J., and Ramsey, J.M., Effects of injection schemes and column geometry on the performance of microchip electrophoresis devices. Anal. Chem.,... 

Free molecular diffusion fKnudsenk This type of diffusion is sometimes called molecular streaming. This flow is induced by collision of gaseous molecules with the pore wall of the capillary (that is when the mean free path is greater than the capillary diameter). Because of the collision of gaseous molecules... 

The researches of Warburg(i), Knudsen(2), Gaede(3), Smoluchowski(4), Buckingham (5), and others (6,7) have demonstrated the properties of the following types of flow (1) Molecular effusion (2) Molecular streaming, or Emudsen flow (3) Poiseuille or stream-line flow (4) Turbulent flow (5) Orifice flow. These may now be considered in turn. 

Several authors (33,27,25) have attempted theories of the dijGFusion process. Urry (33) who considered flow to be a process of molecular streaming, as observed when rarefied gases pass through capillaries, is obviously incorrect for silicate glasses. The other theories (27,25) are based upon more acceptable premises, but do not lead to any notable advance in the study of the subject. They need not therefore be discussed here. 

It is necessary to add that other types of-flow than that of Poiseuille (e.g. molecular streaming, or even activated diffusion) may be occurring in the case of the least permeable membranes cited. The sorting out of flow processes is not yet at all complete. 

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