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| Terms for subject Environment (7397 entries) |
| nitrogen (An essential nutrient in the food supply of plants and the diets of animals. Animals obtain it in nitrogen-containing compounds, particularly amino acids. Although the atmosphere is nearly 80% gaseous nitrogen, very few organisms have the ability to use it in this form. The higher plants normally obtain it from the soil after micro-organisms have converted the nitrogen into ammonia or nitrates, which they can then absorb) | 氮 | |
| nitrogen cycle (The complex set of processes by which crops acquire the large amount of nitrogen they need to make proteins, nucleic acids and other biochemicals of which they are composed, and how the nitrogen returns to the atmosphere) | 氮循环 | |
| nitrogen dioxide (A reddish-brown gas; it exists in varying degrees of concentration in equilibrium with other nitrogen oxides; used to produce nitric acid, NO2) | 二氧化氮 | |
| nitrogen fixation (Assimilation of atmospheric nitrogen by a variety of microorganisms which live freely in soil. Once the nitrogen has been captured by one of the microorganisms, there are many different routes by which it is handled. Some is retained in the soil as decomposing plant matter, waiting to be released and taken up by new crops as a nitrate. That nitrate is produced by nitrifying bacteria living in the soil that thrive on ammonia, which is produced by decaying plant and animal material. In processing nitrogen the nitrifying bacteria produce nitrate that can be absorbed by the roots of plants) | 固氮作用 | |
| nitrogen fixation | 氮气固定作用 | |
| nitrogen monoxide (A colourless gas, soluble in water, ethanol and ether. It is formed in many reactions involving the reduction of nitric acid, but more convenient reactions for the preparation of reasonably pure NO are reactions of sodium nitrite, sulphuric acid, etc.) | 一氧化二氮 | |
| nitrogen oxide (A colorless gas that, at room temperature, reacts with oxygen to form nitrogen dioxide; may be used to form other compounds, NOx) | 一氧化氮 | |
| nitrogen oxides (Oxides formed and released in all common types of combustion; they are formed by the oxidation of atmospheric nitrogen at high temperatures. Introduced into the atmosphere from car exhausts, furnace stacks, incinerators, power stations and similar sources, the oxides include nitrous oxide, nitric oxide, nitrogen dioxide, nitrogen pentoxide and nitric acid. The oxides of nitrogen undergo many reactions in the atmosphere to form photochemical smog) | 氮氧化物 | |
| nitrogenous biochemical oxygen demand | 含氮生化需氧量 | |
| nitrogenous fertiliser (Fertilizer materials, natural or synthesized, containing nitrogen available for fixation by vegetation, such as potassium nitrate or ammonium nitrate) | 氮肥 | |
| nitrosamine (Any one of a class of neutral, usually yellow oily compounds containing the divalent group = NNO) | 亚硝胺 | |
| nitrous oxide | 笑气 | |
| no-convective lift fire phase | 非对流栏火灾阶段 | |
| nocturnal hydraulic lift | 夜间水力提升 | |
| noise (Sound which is unwanted, either because of its effects on humans, its effect on fatigue or malfunction of physical equipment, or its interference with the perception or detection of other sounds) | 噪声 | |
| noise abatement (Measures to reduce noise at the source, to encourage quieter technologies or equipment or to prevent or reduce the propagation of sound. Measures may include the isolation and damping of vibration sources; the replacement of components with quieter parts and material; the enclosure of particularly noisy components; the provision of noise barriers, etc.) | 噪声控制 | |
| noise analysis (Determination of the frequency components that make up a particular noise being studied) | 噪声分析 | |
| noise barrier (Barriers for reducing the propagation of sound: they are widely used in industry and alongside roads and railways to shield receivers from noise sources. Barriers will not reduce the noise on the receivers side, but will increase it, unless the barrier is also covered in absorbing material) | 隔音屏障 | |
| noise control (The process to control the audible sound to an acceptable level) | 噪音控制 | |
| noise disturbance (Noise interferes with communication and interferes with thought processes. Noise interferes with sleep, it causes anger and frustration, and has been implicated as a contributor to various psychological and physiological problems. Noise detracts from the quality of life and the environment) | 噪音干扰 |