Molecular pumps

The feed gas is iatioduced neai the lotoi axis. Enriched and depleted gases are extracted by stationary pitot-like scoops. The location and shape of these tubes, and the baffles within the rotor, gready effect the gas dow which recirculates within the rotor, reaching enrichment equiUbtium at a given feed rate. A vacuum is maintained around most of the rotor. The UF leakage around the stationary axial post is confined to the top of the case by the use of a molecular pump. 

Upper bearing magnets Top scoop Molecular pump... 

J. C. Seou (Aarhus) discovery of the first molecular pump, an ion-transporting enzyme Na+-K+ ATPase. 

In the attempt to overcome the contradictions, the assumption must be made that aside from passive transport in the cell, an active transport of Na ions from the cytoplasm to the external solution is accomplished by the action of peculiar molecular pumps. 

One interesting example of the potential importance of intracellular pH gradients is found in the phenomenon of multidrug resistance (MDR). The MDR protein acts as a molecular pump, actively pumping chemotherapeutic agents out of the cell. Tumor cells, which are susceptible to chemotherapeutics have often a lower intracellular pH [178], which would lead to enhanced accumulation of these drugs in response to the pH differ-... 

Schematic representation of the experimental setup is shown in Fig 1.1. The electrochemical system is coupled on-line to a Quadrupole Mass Spectrometer (Balzers QMS 311 or QMG 112). Volatile substances diffusing through the PTFE membrane enter into a first chamber where a pressure between 10 1 and 10 2 mbar is maintained by means of a turbomolecular pump. In this chamber most of the gases entering in the MS (mainly solvent molecules) are eliminated, a minor part enters in a second chamber where the analyzer is placed. A second turbo molecular pump evacuates this chamber promptly and the pressure can be controlled by changing the aperture between both chambers. Depending on the type of detector used (see below) pressures in the range 10 4-10 5 mbar, (for Faraday Collector, FC), or 10 7-10 9 mbar (for Secondary Electrton Multiplier, SEM) may be established.

The glass coating process requires high gas flows for the sputter processes as well as low hydrocarbon concentration. The only vacuum pump which satisfies these requirements as well as high pumping speed stability over time are turbo-molecular pumps which are used almost exclusively. 

Vacuum technology acceptance specifications for turbo-molecular pumps 11/78... 

Theoretical and experimental investigation of rarefied gas flow in molecular pumps... 

Fig. 11 High pressure, high temperature STM. Sections A-UHV sample manipulator with indirect heating and cooling, B-variable temperature STM, C-magnetically coupled linearrotary transfer arm, D-optical access for analyzers. E-pneumatic air legs and suspension frame, F-turbo molecular pump, G-ion pump. ...

TURBO MOLECULAR TURBO MOLECULAR PUMPING STAGE 3 PUMPING STAGE 2... 

Fig. 1. Photo and illustration of the HRTEM allowing acquisition of images of catalysts under working conditions (4). The microscope is equipped with an FEG, a quadrupole mass spectrometer (QMS), a Gatan image filter (GIF), and a Tietz F144 CCD for data acquisition. The differential pumping system consists of IGPs, turbo molecular pump units (TMP, MDP), and an oil diffusion pump (ODP). The differential pumping stages are set up by apertures inside the TEM column (denoted by black bars) at the objective lens (OL), the first (Cl) condenser aperture, the second (C2) condenser aperture, and the selected area aperture (SA).

For gases or volatile liquids, a small quantity of sample is injected with a microsyringe into a reservoir that is connected to the ionisation chamber via a minute orifice. Because the reservoir is maintained under vacuum and can also be heated, the sample is vaporised. This procedure is called a molecular leak or molecular pumping. 

A two-stage, oil-sealed rotary vane pump is used to back a turbo-molecular pump via a DN25KF line (see below). Under normal working conditions, the pressure in the backing line is (2 to 6) x 10 3mbar. Would the TMP become contaminated by the backing pump ... 

As the filtrate flows into the descending limb of this loop, the NaCl concentration in the fluid surrounding the tubule increases by a factor of four, and osmotic processes cause water to be reabsorbed. At the same time, salts and metabolic products are secreted into the tubular fluid. In the ascending limb, in contrast, the tubular wall is nearly impermeable to water. Here, the epithelial cells contain molecular pumps that transport sodium and chloride from the tubular fluid into the space between the nephrons (the interstitium). These processes are accounted for in considerable detail in the spatially extended model developed by Holstein-Rathlou et al. [14]. In the present model, the reabsorption l rmh in the proximal tubule and the flow resistance Rum are treated as constants. Without affecting the composition much, the proximal tubule reabsorbs close to 60% of the ultrafiltrate produced by the glomerulus. 

But as I pointed out above, there s no reason that parts or subassemblies of irreducibly complex systems can t have one or more other functions, and wordplay can t masquerade as a real explanation. Neither the TTSS, the flagellum, nor any transitions between them have been soberly investigated in a Darwinian framework in the professional science literature. The best place to see this is in a recent paper entitled, Bioinformatics, genomics, and evolution of non-flagellar type-III secretion systems a Darwinian perspective.))27 In it we learn that A type-III secretion system is an exquisitely engineered [emphasis added] molecular pump,... 

The vacuum system of the instrument consists of a four-stage, internally integrated membrane pump with an ultimate pressure of about l-2mbar. The final vacuum is reached with a 70 L/s turbo molecular pump. 

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