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81.
光纤入户是当代通信传输的重要发展目标,而广电网络由于历史原因一直是以同轴电缆进行电视信号的传输,随着时代的不断进步,广电网络也不断地完善着自身的网络品质,大多数地区的广电网络已经完成了光纤到楼栋的网络改造,但是由于改造成本及传输技术等各种因素,光纤入户对大多数广电网络来说还是一种应积极探索的新技术。结合攀枝花广电网络传输模式,对光纤入户技术进行探讨。 相似文献
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Olkin Rhoda; Abrams Kelley; Preston Paul; Kirshbaum Megan 《Canadian Metallurgical Quarterly》2006,51(1):43
Objectives: To contrast families headed by parents with disabilities raising children ages 11-17 years with families headed by parents without disabilities. Study Design: There were 3 sources of data: (a) the National Health Institute Survey (National Center for Health Statistics, 2000), (b) a previous national survey (L. T. T. Barker & V. Maralani, 1997), (c) a new national survey of parents with disabilities (n = 273) and their teens (ages 11-17 years; n = 246) and a control group of parents without disabilities (n = 48) and their teens (n = 37). Main Measure: Participants completed a survey designed for this study. Results: Parents with disabilities were generally quite similar to parents without disabilities, with some notable differences, particularly in employment and income. Deaf parents exhibited certain differences from parents with other disabilities. Conclusion: Survey responses provided a snapshot of parents with disabilities and their families from community samples, including aspects in which disabled and nondisabled participants were similar. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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文章以世界IC市场发展前景为“参照物”,研究、讨论PCB未来市场发展的趋势,以及重点阐述了未来PCB新的巨大市场——数字家电产品的形成问题。 相似文献
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适用于分户热计量的管道暗埋供暖系统 总被引:1,自引:1,他引:0
介绍了适用于分户热计量的4种管道暗埋供暖系统的形式,对管道暗埋供暖系统的管材、安装方法及施工要点进行了分析。 相似文献
88.
农家乐污水中溶解性有机质的三维荧光特性研究 总被引:2,自引:1,他引:1
采用三维荧光光谱(3DEEM)技术考察了农家乐污水中溶解性有机质的三维荧光特性.结果表明,农家乐污水中的有机污染物荧光峰以类蛋白质荧光峰为主,其中高激发波长类色氨酸荧光峰Peak T最强,其次是低激发波长类色氨酸荧光峰Peak S和低激发波长类酪氨酸荧光峰Peak D;综合性农家乐污水的Peak S和Peak D荧光强度比以餐饮为主的农家乐污水的要强.农家乐污水经受纳水体稀释和净化后,类蛋白质荧光强度仍远高于地表水的.其对受纳水体的污染不容忽视. 相似文献
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Yu-yan Yang Lin Fan Jiao Wang Yuan-duo Zhu Xu Li Xin-qi Wang Xu Yan Li Li Yu-jing Zhang Wen-jing Yang Xiao-yuan Yao Xian-liang Wang 《Indoor air》2021,31(5):1391-1401
Household fine particulate matter (PM2.5) pollution greatly impacts residents' health. To explore the current national situation of household PM2.5 pollution in China, a study was conducted based on literature published from 1998 to 2018. After extracting data from the literature in conformity with the requirements, the nationwide household-weighted mean concentration of household PM2.5 (HPL) was calculated. Subgroup analyses of spatial, geographic, and temporal differences were also done. The estimated overall HPL in China was 132.2 ± 117.7 μg/m3. HPL in the rural area (164.3 ± 104.5 μg/m3) was higher than that in the urban area (123.9 ± 122.3 μg/m3). For HPLs of indoor sampling sites, the kitchen was the highest, followed by the bedroom and living room. There were significant differences of geographic distributions. The HPLs in the South were higher than the North in four seasons. The inhaled dose of household PM2.5 among school-age children differed from provinces with the highest dose up to 5.9 μg/(kg·d). Countermeasures should be carried out to reduce indoor pollution and safeguard health urgently. 相似文献