共查询到18条相似文献,搜索用时 78 毫秒
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随着城市化建设进程的不断加快,地铁通信系统的建设规模与速度也在不断扩大与加快。地铁通信系统指的就是可以实现地铁运营活动的语音、数据、图像等信息的传输网络。在进行此系统设计与施工的时候,一定要保证各子系统可以进行正常的运行,利用一些科学技术手段和施工管理保证系统不会受到不必要的影响,进而实现地铁通信系统的可靠、稳定运行。在地铁正式投入使用之后,一定要加强对通信系统的预防性养护与维修,充分发挥系统的作用,实现地铁通信系统的可持续建设。 相似文献
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《农村养殖技术》2007,(9):23-24
禽病已成为困扰我国禽业健康有序发展的主要因素之一。到目前为止,威胁禽业的主要疫病已由上世纪80年代的50多种上升到现在的70~80种,这对我国的兽医提出了严峻挑战。随着我国养殖模式的不断进化以及禽类疫病的突发和不可预测性,越来越多的从事专业禽类兽医需要不断与时俱进,并在实践过程中提高自身专业技能,但传统的兽医教育和培训模式在一定程度上稍显蹩脚。在刚刚结束的第15届世界禽病大会上,美国兽医学院的专家CharLesL、Hofacre就面向禽类的兽医教育和培训新思路(即远程网络授课)和大家进行了长达1小时的讨论。本文就是这次讨论的精彩观点集粹。 相似文献
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采用单因子实验设计,将饲粮粗蛋白质设为3个水平,分别为18%、20%、22%,将鹌鹑分为6个组,每组4个重复,每个重复30只鹌鹑,实验阶段为33~40周龄,研究日粮中蛋白质水平对产蛋性能的影响.结果表明:第2组鹌鹑的产蛋量显著高于第1、3组(P<0.05),产蛋率显著高于第1、3组(P<0.05),第3组的平均蛋重显著高于第1、2组(P<0.05);第2组的料蛋比显著低于第1、3组(P<0.01).说明饲料蛋白质水平为20%时,产蛋性能是最佳的,提高蛋白质水平并没有促进鹌鹑的产蛋性能. 相似文献
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LI Xueyan MENG Jun YI Haibo ZENG Yaqi WANG Jianwen WANG Chuankun REN Wanlu YAO Xinkui YAN Jiabao ZHANG Weilong 《中国畜牧兽医》2022,49(6):2098-2104
【Objective】 The objective of this study was to analyze the effect of different training stages on the performance and heart rate variability(HRV) of Yili horses and to provide data for reference in the conditioning training of 1 600 m distance Yili horses.【Method】 Eight 3-year-old Yili horses (stallions) were selected as test subjects.A 3-month speed specific performance training program was conducted, and a speed test race was organized in the last week of each month of training, and HRV was collected before, immediately after, 0.5 h after, and 1 h after 1 600 m test race.Among them, the time-domain indexes included the mean of all R-R intervals (Mean RR), the standard deviation of all R-R intervals (SDNN), the mean heart rate (Mean HR), the root mean square of the difference between adjacent R-R intervals (RMSSD), the number of adjacent R-R intervals with a difference greater than 50 ms (NN50), and the percentage of adjacent R-R intervals with a difference greater than 50 ms to the total number of heartbeats (pNN50).Frequency domain metrics included very low frequency (VLF), low frequency power (LF), high frequency power (HF) and nonlinear metrics:standard deviation (Y) of all R-R-spacing (SD1), standard deviation (X) of all R-R-spacing (SD2).Consequently, the variability of HRV indexes in horses at different training stages was analyzed.【Result】 The race time in the post training period in 1 600 m speed test race of Yili horses was significantly lower than that in the early training period (P<0.05), and Mean RR, NN50 and pNN50 in the middle and post training periods were significantly lower than that in the early training period (P<0.05).Mean HR in the beginning of training was significantly lower than that in post training (P<0.05).VLF and LF in the end of training were significantly lower than that in the beginning of training (P<0.05).【Conclusion】 Under the conditions of this test, the HRV indexes of 1 600 m test race of Yili horses in different conditioning training stages were analyzed.The outcomes demonstrated that the types of neural activity in Yili horses at the beginning, middle and end of training presented some differences, showing changes of increased sympathetic excitability and decreased parasympathetic excitability, and the horses' athletic performance improved.Therefore, HRV could be considered as an effective tool to evaluate the training load and intensity of Yili horses during training. 相似文献
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猪繁殖性能的提高将为养猪业带来巨大的经济效益 ,目前多数育种者将提高猪的繁殖力作为主要育种目标 ,并用数学遗传学方法和分子育种技术对繁殖性状进行改良。 相似文献
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分析了紫花苜蓿品种的遗传特性、生育期、施肥、田间管理、地老虎虫害等因素对紫花苜蓿粗蛋白质含量的影响。结果表明:紫花苜蓿粗蛋白质含量在不同品种上存在差异。从营养生长期到结荚期,粗蛋白质CP含量呈逐步下降的超势;施肥能够显著增加苜蓿产量,但对CP含量影响不明显;田间杂草、地老虎等既影响苜蓿生长又降低苜蓿CP含量。 相似文献
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为研究封片时间对经过脂质染色的细胞爬片保存效果的影响,采用原代肝细胞体外培养的方法培养大鼠肝细胞并制作细胞爬片,油红。染色,光学显微镜成像系统观察不同时间段细胞爬片的封片。结果表明,染色后立即封湿片的细胞爬片结构显示细腻;而染色后充分干燥后再封片的细胞爬片细胞表面出现皱缩皲裂,与前者比较有极显著差异。从而说明不同的封片时间对脂质染色的细胞爬片保存效果的影响。 相似文献
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《科技视界》2014,(13)
<正>0 Introduction Learning to read is one of the most crucial learning processes students are involved in at school,and the ability to read profoundly influences academic achievement.Therefore,improving the reading ability of students is one of the primary goals of English classroom teaching.This study aims to examine the usage of English reading strategies in senior high school classroom teaching and what kinds of reading 相似文献