拡散・ンプ

WordNet

supply in great quantities; "Pump money into a project"
a low-cut shoe without fastenings
a mechanical device that moves fluid or gas by pressure or suction
deliver forth; "pump bullets into the dummy"
draw or pour with a pump
flow intermittently
move up and down; "The athlete pumps weights in the gym"
operate like a pump; move up and down, like a handle or a pedal; "pump the gas pedal"
question persistently; "She pumped the witnesses for information"
raise (gases or fluids) with a pump
(physics) the process in which there is movement of a substance from an area of high concentration of that substance to an area of lower concentration
the spread of social institutions (and myths and skills) from one society to another

PrepTutorEJDIC

『ポンプ』 / 《単数形で》ポンプで空気(ガス)を入れること / 《副詞[句]を伴って》〈気体・液体〉‘を'『ポンプで入れる』(『出す』) / …‘から'ポンプで水(など)を除く《+『out』+『名』,+『名』+『out』》 / …‘に'ポンプで空気(など)を満たす《+『up』+『名』,+『名』+『up』》 / (ポンプのハンドルのように)…‘を'上下(前後)に動かす / 《話》(…について)〈人〉‘を'あの手この手で問いただす(聞き出す)《+『名』+『for』(『about』)+『名』》 / 《話》(人に)〈知識など〉‘を'詰め込む《+『名』+『into』+『名』〈人〉》;(人から)〈情報など〉‘を'引き出す《+『名』+『out of』+『名』〈人〉》 / ポンプを使う / (ポンプのように)上下に動く,鼓動する / 〈水が〉噴出する
パンプス(ひもや金具がなく,甲のあいた靴)
放散,発散,拡散[作用] / 普及,流布 / (文体などの)散漫,冗漫

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/06/27 22:02:57」(JST)

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Six inch oil diffusion pump.

Diffusion pumps use a high speed jet of vapor to direct gas molecules in the pump throat down into the bottom of the pump and out the exhaust. Invented in 1915 by Wolfgang Gaede^[1] using mercury vapor, and improved by Irving Langmuir and W. Crawford, they were the first type of high vacuum pumps operating in the regime of free molecular flow, where the movement of the gas molecules can be better understood as diffusion than by conventional fluid dynamics. Gaede used the name diffusion pump since his design was based on the finding that gas cannot diffuse against the vapor stream, but will be carried with it to the exhaust.^[2] However, the principle of operation might be more precisely described as gas-jet pump, since diffusion plays a role also in other high vacuum pumps. In modern text books, the diffusion pump is categorized as a momentum transfer pump. The diffusion pump is widely used in both industrial and research applications. Most modern diffusion pumps use silicone oil or polyphenyl ethers as the working fluid. Cecil Reginald Burch discovered the possibility of using silicone oil in 1928.^[3]

Oil diffusion pumps

The oil diffusion pump is operated with an oil of low vapor pressure. Its purpose is to achieve higher vacuum (lower pressure) than is possible by use of positive displacement pumps alone. Although its use has been mainly associated within the high-vacuum range (down to 10⁻⁹ mbar), diffusion pumps today can produce pressures approaching 10⁻¹⁰ mbar when properly used with modern fluids and accessories. The features that make the diffusion pump attractive for high and ultra-high vacuum use are its high pumping speed for all gases and low cost per unit pumping speed when compared with other types of pump used in the same vacuum range. Diffusion pumps cannot discharge directly into the atmosphere, so a mechanical forepump is typically used to maintain an outlet pressure around 0.1 mbar.

Diffusion pumps used on the Calutron mass spectrometers during the Manhattan Project.

Diagram of an oil diffusion pump

The high speed jet is generated by boiling the fluid and directing the vapor through a jet assembly. Note that the oil is gaseous when entering the nozzles. Within the nozzles, the flow changes from laminar, to supersonic and molecular. Often several jets are used in series to enhance the pumping action. The outside of the diffusion pump is cooled using either air flow or a water line. As the vapor jet hits the outer cooled shell of the diffusion pump, the working fluid condenses and is recovered and directed back to the boiler. The pumped gases continue flowing to the base of the pump at increased pressure, flowing out through the diffusion pump outlet, where they are compressed to ambient pressure by the secondary mechanical forepump and exhausted.

Unlike turbomolecular pumps and cryopumps, diffusion pumps have no moving parts and as a result are quite durable and reliable. They can function over pressure ranges of 10⁻¹⁰ to 10⁻² mbar. They are driven only by convection and thus have a very low energy efficiency.

One major disadvantage of diffusion pumps is the tendency to backstream oil into the vacuum chamber. This oil can contaminate surfaces inside the chamber or upon contact with hot filaments or electrical discharges may result in carbonaceous or siliceous deposits. Due to backstreaming, oil diffusion pumps are not suitable for use with highly sensitive analytical equipment or other applications which require an extremely clean vacuum environment, but mercury diffusion pumps may be in the case of ultra high vacuum chambers used for metal deposition. Often cold traps and baffles are used to minimize backstreaming, although this results in some loss of pumping ability.

The oil of a diffusion pump cannot be exposed to the atmosphere when hot. If this occurs, the oil will burn and has to be replaced.

Steam ejectors

Plot of pumping speed as a function of pressure for a diffusion pump.

Early Langmuir mercury diffusion pump (vertical column) and its backing pump (in background), about 1920. The diffusion pump was widely used in manufacturing vacuum tubes, the key technology which dominated the radio and electronics industry for 50 years.

The steam ejector is a popular form of diffusion pump for vacuum distillation and freeze-drying. A jet of steam entrains the vapour that must be removed from the vacuum chamber. Steam ejectors can have a single or multiple stages, with and without condensers in between the stages.

Compressed-air ejectors

One class of diffusion vacuum pumps is the multistage compressed-air driven ejector. It is very popular in applications where objects are moved around using suction cups and vacuum lines.

References

^ Gaede, W. (1915). "Die Diffusion der Gase durch Quecksilberdampf bei niederen Drucken und die Diffusionsluftpumpe". Annalen der Physik 46 (3): 357. Bibcode:1915AnP...351..357G. doi:10.1002/andp.19153510304.
^ D. G. Avery and R. Witty (1947). "Diffusion pumps: a critical discussion of existing theories". Proc. Phys. Soc. 59 (6): 1016–1030. Bibcode:1947PPS....59.1016A. doi:10.1088/0959-5309/59/6/313.
^ C. R. Burch (1928). "Oils, greases and high vacua". Nature 122 (3080): 729. Bibcode:1928Natur.122..729B. doi:10.1038/122729c0.

External links

An oil diffusion pump built from glass by the Arizona State University Main

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English Journal

Quantitative calculation of the role of the Na(+),K(+)-ATPase in thermogenesis.

Clarke RJ, Catauro M, Rasmussen HH, Apell HJ.SourceSchool of Chemistry, University of Sydney, Sydney, NSW 2006, Australia. r.clarke@chem.usyd.edu.au
Biochimica et biophysica acta.Biochim Biophys Acta.2013 Oct;1827(10):1205-12. doi: 10.1016/j.bbabio.2013.06.010. Epub 2013 Jul 11.
The Na(+),K(+)-ATPase is accepted as an important source of heat generation (thermogenesis) in animals. Based on information gained on the kinetics of the enzyme's partial reactions we consider via computer simulation whether modifications to the function of the combined Na(+),K(+)-ATPase/plasma mem
PMID 23850548

The axial rearrangement mixer: working principles and in-depth investigation.

Goovaerts R, Vandermeersch T, De Beeck JO, Eghbali H, Desmet G.SourceVrije Universiteit Brussel, Brussels, Belgium.
Electrophoresis.Electrophoresis.2013 Oct 1. doi: 10.1002/elps.201300270. [Epub ahead of print]
In the current paper, an axial rearrangement mixer is studied. The mixer aims to flatten out occasional composition fluctuations originating from the pump. In a first phase, dispersion in a single mixer channel is investigated using pulses introduced by a dedicated injection pulse generator. The mix
PMID 24114997

Dynamic modulation of spike timing-dependent calcium influx during corticostriatal upstates.

Evans RC, Maniar YM, Blackwell KT.SourceThe Krasnow Institute for Advanced Studies, George Mason University, Fairfax, Virginia; and.
Journal of neurophysiology.J Neurophysiol.2013 Oct;110(7):1631-45. doi: 10.1152/jn.00232.2013. Epub 2013 Jul 10.
The striatum of the basal ganglia demonstrates distinctive upstate and downstate membrane potential oscillations during slow-wave sleep and under anesthetic. The upstates generate calcium transients in the dendrites, and the amplitude of these calcium transients depends strongly on the timing of the
PMID 23843436

Japanese Journal

Ultralarge transient optical gain from tensile-strained, n-doped germanium on silicon by spin-on dopant diffusion

Xu Xuejun,Wang Xiaoxin,Nishida Keisuke,Takabayashi Koki,Sawano Kentarou,Shiraki Yasuhiro,Li Haofeng,Liu Jifeng,Maruizumi Takuya
Appl. Phys. Express 8(9), 092101, 2015-08-18
… 10<sup>19</sup>cm<sup>−3</sup>is achieved by phosphorus diffusion from a spin-on dopant source. … The transmittance of the germanium film is clearly increased upon increasing the pump power. …
NAID 150000111232

コンクリートに混和したアルギニンの存在形態と溶出機構

佐藤和博,上月康則,多良千鶴 [他],西村博一,中西敬,上田隆雄,山中亮一
材料 64(5), 417-423, 2015
… And there were adsorption equilibriums between arginine and concrete constituents (cement paste and aggregate) at mildly alkaline pH. A part of arginine has a positive charge at mildly alkaline pH. In addition, the concrete block containing arginine was put in the tank poured marine water by pump. … The elution of arginine was considered to be affected by not only diffusion but adsorption equilibrium at stable phase in analogy with Ca in the concrete. …
NAID 130005070700

低水透過MEAを用いたDMFCの小型化技術

八木亮介,佐藤裕輔,秋田征人,本郷卓也,富松師浩
日本機械学会論文集 81(821), 14-00237-14-00237, 2015
… Water permeation controlled layer which has lower permeability (K~10 -14 m 2) than conventional micro porous layer (K~10 -13 m 2) was sandwiched between anode gas diffusion layer and anode catalyst layer. … This layer blocks liquid water permeation from anode gas diffusion layer to anode catalyst layer and enhances water diffusion from cathode to anode. …
NAID 130005005014