Total pressure

About: Total pressure is a research topic. Over the lifetime, 5199 publications have been published within this topic receiving 66658 citations.

Growth and mitochondrial respiration of mungbeans (Phaseolus aureus Roxb.) germinated at low pressure

Abstract: Mungbean (Phaseolus aureus Roxb.) seedlings were grown hypobarically to assess the effects of low pressure (21-24 kilopascals) on growth and mitochondrial respiration. Control seedlings grown at ambient pressure (101 kilopascals) were provided amounts of O2 equivalent to those provided experimental seedlings at reduced pressure to factor out responses to O2 concentration and to total pressure. Respiration was assayed using washed mitochondria, and was found to respond only to O2 concentration. Regardless of total pressure, seedlings grown at 2 millimoles O2 per liter had higher state 3 respiration rates and decreased percentages of alternative respiration compared to ambient (8.4 millimoles O2 per liter) controls. In contrast, seedling growth responded to total pressure but not to O2 concentration. Seedlings were significantly larger when grown under low pressure. While low O2 (2 millimoles O2 per liter) diminished growth at ambient pressure, growth at low pressure in the same oxygen concentration was enhanced. Respiratory development and growth of mungbean seedlings under low pressure is unimpaired whether oxygen or air is used as the chamber gas, and further, low pressure can improve growth under conditions of poor aeration.

Chemistry of SiO2 Plasma Deposition

Abstract: The chemistry of deposition from undiluted and He‐diluted mixtures was studied by line‐of‐sight mass spectrometry of plasma species coupled with analysis of film IR absorption and dielectric properties. It was found that if RF power is sufficient to generate an O atom supply well in excess of that needed to convert all of the to , then clean IR spectra and high dielectric strength are obtained independent of dilution. Under these plasma conditions, many gas‐phase products of the form were detected. Their concentration increased steeply with the partial pressure of the reactants , and they are the likely source of the downstream particles and deposition rate loss which were seen at 130 Pa of reactant pressure. Reduction of reactant partial pressure to 13 Pa either by He dilution or by undiluted total pressure reduction eliminated these problems. No other effects of He dilution could be detected either in the plasma chemistry or in the film properties. Both concentration and electron trapping rate in the films were much higher than in thermal oxide and were unaffected by He dilution. There is some evidence that He plasma treatment does improve Si interface quality.