“osmosis”的概念、定义、翻译、参考文献-科学参考

osmosis

Physics

The passage of a solvent through a semipermeable membrane separating two solutions of different concentrations. A semipermeable membrane is one through which the molecules of a solvent can pass but the molecules of most solutes cannot. There is a thermodynamic tendency for solutions separated by such a membrane to become equal in concentration, the water (or other solvent) flowing from the weaker to the stronger solution. Osmosis will stop when the two solutions reach equal concentration, and can also be stopped by applying a pressure to the liquid on the stronger-solution side of the membrane. The pressure required to stop the flow from a pure solvent into a solution is a characteristic of the solution, and is called the osmotic pressure (symbol Π‎). Osmotic pressure depends only on the concentration of particles in the solution, not on their nature (i.e. it is a colligative property). For a solution of n moles in volume V at thermodynamic temperature T, the osmotic pressure is given by Π‎V=nRT, where R is the gas constant. Osmotic-pressure measurements are used in finding the relative molecular masses of compounds, particularly macromolecules. A device used to measure osmotic pressure is called an osmometer.

The distribution of water in living organisms is dependent to a large extent on osmosis, water entering the cells through their membranes. A cell membrane is not truly semipermeable as it allows the passage of certain solute molecules; it is described as partially permeable. Animals have evolved various means to counteract the effects of osmosis; in plant cells, excessive osmosis is prevented by the pressure exerted by the cell wall, which opposes the osmotic pressure.

Chemistry

The passage of a solvent through a semipermeable membrane separating two solutions of different concentrations. A semipermeable membrane is one through which the molecules of a solvent can pass but the molecules of most solutes cannot. There is a thermodynamic tendency for solutions separated by such a membrane to become equal in concentration, the water (or other solvent) flowing from the weaker to the stronger solution. Osmosis will stop when the two solutions reach equal concentration, and can also be stopped by applying a pressure to the liquid on the stronger-solution side of the membrane. The pressure required to stop the flow from a pure solvent into a solution is a characteristic of the solution, and is called the osmotic pressure (symbol Π‎). Osmotic pressure depends only on the concentration of particles in the solution, not on their nature (i.e. it is a colligative property). For a solution of n moles in volume V at thermodynamic temperature T, the osmotic pressure is given by Π‎V = nRT, where R is the gas constant. Osmotic-pressure measurements are used in finding the relative molecular masses of compounds, particularly macromolecules. A device used to measure osmotic pressure is called an osmometer.

Chemical Engineering

The movement by diffusion of a fluid or solvent from a low to a more concentrated solution through a semi-permeable membrane. The movement causes the concentrations on either side of the membrane to equalize. The osmotic pressure is the equilibrium pressure difference between the fluids of differing composition on either side of the membrane. It is a function of the solute concentration and is independent of the number of ions or molecules in solution. Compare reverse osmosis.

Biology

The net movement of water molecules from a dilute (hypotonic) solution to a more concentrated (hypertonic) solution through a differentially permeable membrane. The distribution of water in living organisms is dependent to a large extent on osmosis, water entering and leaving the cells through their partially permeable plasma membranes. The pressure required to stop the flow of pure water into a solution across a partially permeable membrane is a characteristic of the solution, and is called the osmotic pressure. In animal physiology osmosis is described in terms of osmolarity (see concentration), with a net movement of water occurring from a region of low osmolarity to one of higher osmolarity. Plant physiologists use the concept of water potential, so that water moves from an area of high (less negative) water potential to an area of low (more negative) water potential (see also plasmolysis; turgor). Animals have evolved various means to counteract the effects of osmosis (see osmoregulation). See also oncotic pressure; tonicity.

Geology and Earth Sciences

The movement of water or of another solvent from a region of low solute concentration to one of higher concentration through a partially permeable membrane. It is an important mechanism in the uptake of water by plants.

Geography

The passage of a weaker solution to a stronger solution through a semi-permeable membrane. In soils, the more dilute soil moisture passes by osmotic pressure into plant roots. Salinization causes reverse osmosis in soil, where higher concentrations of salt in the soil water draw water from the plant roots, causing crops to wither, and perhaps die. See Kotzer (2005) Desalinisation 185, 1–3.

单词	osmosis
释义	osmosis Physics The passage of a solvent through a semipermeable membrane separating two solutions of different concentrations. A semipermeable membrane is one through which the molecules of a solvent can pass but the molecules of most solutes cannot. There is a thermodynamic tendency for solutions separated by such a membrane to become equal in concentration, the water (or other solvent) flowing from the weaker to the stronger solution. Osmosis will stop when the two solutions reach equal concentration, and can also be stopped by applying a pressure to the liquid on the stronger-solution side of the membrane. The pressure required to stop the flow from a pure solvent into a solution is a characteristic of the solution, and is called the osmotic pressure (symbol Π‎). Osmotic pressure depends only on the concentration of particles in the solution, not on their nature (i.e. it is a colligative property). For a solution of n moles in volume V at thermodynamic temperature T, the osmotic pressure is given by Π‎V=nRT, where R is the gas constant. Osmotic-pressure measurements are used in finding the relative molecular masses of compounds, particularly macromolecules. A device used to measure osmotic pressure is called an osmometer. The distribution of water in living organisms is dependent to a large extent on osmosis, water entering the cells through their membranes. A cell membrane is not truly semipermeable as it allows the passage of certain solute molecules; it is described as partially permeable. Animals have evolved various means to counteract the effects of osmosis; in plant cells, excessive osmosis is prevented by the pressure exerted by the cell wall, which opposes the osmotic pressure. Chemistry The passage of a solvent through a semipermeable membrane separating two solutions of different concentrations. A semipermeable membrane is one through which the molecules of a solvent can pass but the molecules of most solutes cannot. There is a thermodynamic tendency for solutions separated by such a membrane to become equal in concentration, the water (or other solvent) flowing from the weaker to the stronger solution. Osmosis will stop when the two solutions reach equal concentration, and can also be stopped by applying a pressure to the liquid on the stronger-solution side of the membrane. The pressure required to stop the flow from a pure solvent into a solution is a characteristic of the solution, and is called the osmotic pressure (symbol Π‎). Osmotic pressure depends only on the concentration of particles in the solution, not on their nature (i.e. it is a colligative property). For a solution of n moles in volume V at thermodynamic temperature T, the osmotic pressure is given by Π‎V = nRT, where R is the gas constant. Osmotic-pressure measurements are used in finding the relative molecular masses of compounds, particularly macromolecules. A device used to measure osmotic pressure is called an osmometer. Chemical Engineering The movement by diffusion of a fluid or solvent from a low to a more concentrated solution through a semi-permeable membrane. The movement causes the concentrations on either side of the membrane to equalize. The osmotic pressure is the equilibrium pressure difference between the fluids of differing composition on either side of the membrane. It is a function of the solute concentration and is independent of the number of ions or molecules in solution. Compare reverse osmosis. Biology The net movement of water molecules from a dilute (hypotonic) solution to a more concentrated (hypertonic) solution through a differentially permeable membrane. The distribution of water in living organisms is dependent to a large extent on osmosis, water entering and leaving the cells through their partially permeable plasma membranes. The pressure required to stop the flow of pure water into a solution across a partially permeable membrane is a characteristic of the solution, and is called the osmotic pressure. In animal physiology osmosis is described in terms of osmolarity (see concentration), with a net movement of water occurring from a region of low osmolarity to one of higher osmolarity. Plant physiologists use the concept of water potential, so that water moves from an area of high (less negative) water potential to an area of low (more negative) water potential (see also plasmolysis; turgor). Animals have evolved various means to counteract the effects of osmosis (see osmoregulation). See also oncotic pressure; tonicity. Geology and Earth Sciences The movement of water or of another solvent from a region of low solute concentration to one of higher concentration through a partially permeable membrane. It is an important mechanism in the uptake of water by plants. Geography The passage of a weaker solution to a stronger solution through a semi-permeable membrane. In soils, the more dilute soil moisture passes by osmotic pressure into plant roots. Salinization causes reverse osmosis in soil, where higher concentrations of salt in the soil water draw water from the plant roots, causing crops to wither, and perhaps die. See Kotzer (2005) Desalinisation 185, 1–3.
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