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71.
现有平流组合加热式蔬菜脱水机存在热交换不充分和干燥速度慢等问题。对现有设备进行了穿流组合加热技术改造:将送风管和引风管连接管的直径自上而下依次减小,满足了各层干燥箱对送风量和引风量的不同要求;采用冲孔板制造输送链板,满足了穿流供风的要求;采用供风管变截面供风技术,提高了供风的均匀性。设备改造后,分别对胡萝卜和甘蓝两种蔬菜进行了脱水干燥对比试验。结果表明,采用穿流组合加热时,不仅干燥速度快,而且其平均单位脱水的能耗分别由平流组合加热的7.03,7.29MJ/kg下降为6.83,6.65MJ/kg。 相似文献
72.
Juliano Lino Ferreira José Eustáquio de Souza Carneiro Alexsandro Lara Teixeira Fabiéli Fortunata de Lanes Paulo Roberto Cecon Aluízio Borém 《Euphytica》2007,153(1-2):165-170
This study was conducted in Brazil in order to assess the potential risk posed by gene escape from transgenic into non-transgenic plants and wild populations. A new methodology was applied to evaluate the gene flow between common bean cultivars, by means of a specially delineated experiment in two stages. The first stage consisted of the planting of one cultivar with violet flowers (BB) as pollen source (‘Diamante Negro’), and a receiver (‘Talismã’) with white flowers (bb), at different distances. The source was sown in the center of the area. The pollen receiver cultivar was sown, in concentrical squares around it. At maturity, the rows were sampled at varied distances from the source in the four cardinal directions. In the second stage, the sampled seeds of the previous stage were sown, and the percentage of outcrossing was evaluated during flowering through the presence of violet flowers (Bb). The highest frequency of natural hybrids, 0.136%, occurred at a distance of 0.5 m between the cultivars. The natural outcrossing rate was practically zero beyond a distance of 3.25 m. 相似文献
73.
Poor reproductive development in yams (Dioscorea spp.) has often been attributed to the polyploid nature of the crop. In this study, flow cytometry was used to determine
the ploidy level of 53 accessions of Dioscorea alata, mostly from West African countries, Chad and Puerto Rico. Nuclei were isolated from young leaf material and stained with
DAPI(4,6-diamidino-2-phenylindole). The nuclear genome size (2C) was measured as an indicator of the ploidy level. Dioscorea rotundata genotypes with known ploidy levels were used as standards. The results showed that the majority of plants were hexaploid
(84.9%) with a smaller percentage of tetraploids (15.1%). A higher number of male plants were hexaploid than tetraploids.
This is at variance with earlier findings, which reported that hexaploid male plants are rare. Higher ploidy levels were not
directly related to sparse or erratic flowering as previously reported as profuse flowering occurred in some male hexaploid
accessions. These findings have important implications for yam breeding in relation to yam genetic resources.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
74.
Comparison of nuclear DNA content of citrus rootstock populations by flow cytometry analysis 总被引:2,自引:0,他引:2
Citrus species are widely grown in the world. Plant characteristics of the rootstock populations used for orange, lemon, mandarin and grapefruit cultivars should be known as well as those of the cultivars that help true‐to‐type nursery plant production. In this study, cell nuclei were isolated from leaf tissues of seedlings of trifoliate orange, sour orange, rough lemon,‘Volkamer’ lemon,‘Cleopatra’ mandarin,‘Hyokan’, ‘Sanbokan’, ‘Kinkoje’, ‘Carrizo’ citrange and ‘Swingle’ citrumelo, and then fluorescence intensities were measured on propidium iodide‐stained nuclei by flow cytometry. Nuclei isolated from the triploid ‘Tahiti’ lime with a known nuclear genome size were used as the internal standard to estimate the nuclear DNA content of Citrus seedling populations in absolute units. Results obtained from cytograms and histograms indicated that all seedlings analyzed were diploid. In addition, differences between the species for nuclear DNA content were also found to be significant. ‘Hyokan’ seedlings had the biggest genome size, 0.984 pg/2C, whereas trifoliate orange seedlings had the smallest genome size, 0.678 pg/2C. Flow cytometry analysis could be used for obtaining accurate and rapid results for cytological observations of seedling populations of Citrus. 相似文献
75.
本文根据灌溉配水渠系的运行特点,提出在一定轮期和来水流量限制条件下实现下级配水渠最优组合及其配水时间最优排序的一种0-1规划模型,实例运算表明,这种方法可有效减少无效弃水和闸门调节次数,同时对渠道横断面的设计有参考意义。 相似文献
76.
77.
试验表明,三道湾水电站原设计存在以下问题:泄洪排沙洞单独全开运行工况下,其进口上方存在贯通性吸气漏斗漩涡;正常溢洪洞进口侧收缩十分严重,泄流量不足,闸后存在水翅、折冲波等不良流态,下游消能效果不佳;针对实际情况,试验通过在泄洪排沙洞进口增设消涡格栅,在正常溢洪洞进口设置椭圆形导墙、延长闸后收缩段,下游采用扩散挑流消能等措施,很好地解决了上述问题。 相似文献
78.
海河二道闸和防潮闸优化调度研究 总被引:1,自引:0,他引:1
汛期为腾空海河河道并保证二道闸下咸水不致上溯,二道闸闸下水位应控制在1.0m左右。利用一维非恒定流模型对海河自西河闸至入海口河段进行数值模拟,研究了西河闸分流量为80、100、120m3/s3种情况下,海河防潮闸和二道闸优化调度结果。 相似文献
79.
80.
聂杰 《中国农村水利水电》1992,(2)
江苏太湖平原地区灌溉水源丰富,排水通畅,但由于年际水量分配不均,干旱仍时有发生。根据这一情况,对灌溉水的利用问题进行了研究。在大、小区水量平衡的基础上,提出了灌溉水的回归系数和回归水的重复利用系数,以及灌溉水的重复利用系数。为本区水利规划、用水管理和供水规划提供了可靠的依据。 相似文献