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121.
介绍一种阻性和抗性组合式消声箱的试验,通过不同结构的组合几种防灰结构消声元件的性能参数进行试验研究。结果表明,防灰结构消声器的经验设计法是可行的,通流断面的变化对消声器的压力损失影响较大。 相似文献
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Allison J. Abell 《Behavioral ecology and sociobiology》1997,41(4):217-226
The association between spatial proximity and paternity was studied in a population of the striped plateau lizard, Sceloporus virgatus. The relationship between estimated mating success and male phenotypic traits was examined for a sample of 55 males. DNA
samples were obtained from 13 female-offspring families. The males with the closest spatial proximity to each female were
tested as possible sires within each family. Fingerprinting with two multilocus hypervariable minisatellite probes revealed
a strong correspondence between male-female spatial proximity and actual paternity. Paternity could be assigned for 72 of
the 100 hatchlings. Most hatchlings with identifiable sires were attributed to a male with the highest category of spatial
proximity to the mother. However, there was a low to moderate level of multiple paternity within clutches, and for some clutches
probable sires could not be identified even though the most likely behavioural candidates were tested. Thus, nonterritorial
males or other males lacking strong social and spatial relationships with females may achieve some degree of reproductive
success. Analysis of mating success revealed that male success increased with body size, up to a point beyond which larger
size conferred no advantage.
Received: 7 January 1997 / Accepted after revision: 16 June 1997 相似文献
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城市污水处理厂鼓风机房通风设计分析 总被引:1,自引:0,他引:1
本文介绍了城市污水处理厂鼓风机房通风设计的重要性,分析了鼓风机房的进气系统及排气系统的设计要点,并介绍了肇庆污水处理厂的鼓风机房设计实例。 相似文献
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以平顶山天安煤业股份有限公司一矿扇风机噪声治理为例,针对煤矿扇风机噪声强度大、衰减慢、治理难度大等特点,提出了一种综合治理措施,把消声、隔声、吸声等有机结合起来,使治理后的扇风机房边界噪声达到了《工业企业厂界环境噪声排放标准》(GB 12348-2008)中的噪声限定规定,风井口处的噪声满足了《工业企业噪声控制设计规范》(GBJ 87-85)中的要求,使企业做到了达标排放。 相似文献
127.
为了提高高压静电分选Ag与聚对苯二甲酸乙二醇酯(polyethylene terephthalate,简称PET)的效率,寻求可产生较佳分选效率的电压、转速、极间距和电晕线角度。采用自制的线辊式静电分选机,通过单因素实验和部分因子实验,研究了不同条件下Ag与PET的分选效率。结果表明:将Ag与PET从二者混合物中有效分选出来的电压为25~30k V、转速为60~75 r/min、极间距为60~70 mm、电晕极角度为50~60°;当电压为30 k V、转速为75 r/min、电晕极距离为70 mm和电晕极角度为60°时,Ag的分选效率达到了最大值为99.60%,PET的分选效率也达到了最大值为99.98%,为线辊式静电分选机结构设计与参数优化提供了参考。 相似文献
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This study was designed to explore the cultivation measures for the high yield of forage oats (Avena sativa L.) in the eastern mountain dryland of Qinghai Province of China. Taking 'Jiayan No.2' oat as the research material, the effects of different sowing dates, row spacing, sowing amount, and fertilizing amount on hay yield were studied by orthogonal experiment design with four factors and three levels. Sowing date, row spacing, sowing amount, and fertilizer amount all affected the hay yield of forage oats. Among them, the sowing date had the greatest influence, reaching an extremely significant level in the 3-year experiment and 3-year average (P < 0.01), followed by fertilizing amount and row spacing (P < 0.05). The effects of sowing amount on oat hay yield were relatively small (P > 0.05). Principal component analysis showed that the sowing date contributed the most to oat hay yield, followed by sowing amount, fertilizing amount, and row spacing. According to the comprehensive score and ranking of each principal component, we found that the early sowing treatment combination was superior to the late sowing treatment combination, and the optimal treatment combination was treatment 3, with a comprehensive score of 2.533. Treatment 3 (early sowing, 20 cm row spacing, sowing amount 240 kg/hm2, and fertilizing amount of 150 kg/hm2 N2O and 300 kg/hm2 P2O5) and treatment 1 (early sowing, 10 cm row spacing, 120 kg/hm2 sowing amount, and fertilizing amount of 37.5 kg/hm2 N2O and 75 kg/hm2 P2O5) always ranked first and second, the average yield of hay in 3 years was 7 942.21 kg/hm2 and 7 321.61 kg/hm2, respectively, and there was no significant difference in hay yield after multiple tests. When forage oats were planted in the eastern mountain dryland of Qinghai Province, the optimal planting conditions were early sowing in good time (mid and early April), row spacing of 20 cm, sowing amount of 240 kg/hm2, and fertilization amount of 150 kg/hm2 N2O and 300 kg/hm2 P2O5 © 2022 Science Press. All rights reserved. 相似文献