The structure characteristics of metal foams were introduced.The boiling heat transfer performance in metal foams,which influenced by aspects include bubble growth speed,diameter,growth phenomenon,and the structure parameters of porosity and pore density of metal foams were reviewed.Finally,the research direction on boiling heat transfer in metal foams was proposed.
In this paper,a program of recovering waste heat from waste water of furnace slag was presented according to the features of the waste water.In this program,the separated-type heat pipe heat exchanger was used and its structural features were described.
2001年,从日本神奈川农业综合试验研究所引进梨树品种'明水'[(新水×42-6(幸水×云井)].经过连续5年的引种观察,被认为是1个优质早熟梨新品种,日前通过省级专家鉴定.现将该品种主要特征介绍如下:
The study treated the seedlings of watermelon pot planted in greenhouse with 5-aminolevulinic acid （ALA） at 504200 mg/L and studied their photosynthetic characteristics, carbohydrate accumulations, anti-oxidative enzyme activities and MDA contents at low temperature under weak light. It was shown that the treatments with exogenous ALA could significantly raise the net photosynthetic rate, stomatal conductance and transpiration rate of the leaves of watermelon seedlings. ALA treatments raised the activities of such anti-oxidative enzymes as SOD and POD,but exerted little influence on the CAT and APX activities in the leaves of watermelon seedlings, which implied that the ALA treatments enhanced the metabolism of active oxygen species by raising the SOD and POD activities in watermelon plants, thus maintaining the cellular photosynthetic capacity. 30 days after the ALA treatments, the dry weights, starch and solvable sugar contents of treated watermelon plants increased separately by 42%-54%, 62.2%-207.0% and 32.0%-87.1% compared with those of the control plants. The above results indicated that ALA treatments could improve the activities of anti-oxidative enzymes in watermelon seedling at low temperature under weak light,and promoted the photosynthesis and photosynthate accumulations as well as the plant growth.
