| 宋国柱.θ-类算子的谱及其导算子的值域[J].数学研究及应用,1987,7(1):49~54 |
| θ-类算子的谱及其导算子的值域 |
| THE SOILLESS CULTURE IN WEST EUROPE AND NORTH AMERICA |
| 投稿时间：1983-04-30 |
| DOI：10.3770/j.issn:1000-341X.1987.01.010 |
| 中文关键词: |
| 英文关键词: |
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| 摘要点击次数: 1984 |
| 全文下载次数: 847 |
| 中文摘要: |
| 西欧、北美的无土栽培以基质栽培为主,NFT面积很小。西欧作物种植比例,蔬菜占80％以上,花卉和其他作物较少。基质栽培中以岩棉发展最快,今后发展的动向,岩棉板栽培仍将占压倒的优势,袋培次之,砂培和NFT也将有一定的发展。温室节能,作物生理及无土栽培设备的改进,仍是今后研究的重点。 |
| 英文摘要: |
| The main types of soilless culture are aggregate hydroponic systems in West Europe and North America, NFT is rather small area. In these systems vegetable crops are planted more than 80% in West Europe. Flower other crops are much less than vegetables. Among growing mediums in hydroponic system rockwool has been increacing rapidly. In near future the Development of rockwool slab culture will still be the 1st used than other substrates, bag culture the 2nd, sand culture and NFT the 3rd. Scientists will pay more attention in research on greenhouse energy saving, crop physiology and facilities of hydroponic system improvement. |
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