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排序方式: 共有357条查询结果,搜索用时 265 毫秒
41.
针对当前我国在原密闭式鸡舍的横向通风与开放式或半开放式鸡舍的自然通风方式改造成纵向通风过程中存在的一些问题,着重分析讨论了鸡舍纵向通风系统的通风换气量与舍内风速取值,进气口面积与位置的确定,风机的选型及其不同季节的运行管理等问题。为今后我国不同类型鸡舍的纵向通风系统的设计与应用提供参考。 相似文献
42.
以持久收入假说为基础,利用多因素线性效用函数构建多元回归模型,估计了中国农村居民的住房消费函数,并估算出了平均消费倾向。对农村住房平均消费倾向及其影响因素进行了实证分析。结果表明,实际收入增长率、恩格尔系数、住房面积、居民平均储蓄倾向、消费习惯、住房面积与价值是农村住房平均消费倾向的主要影响因素。 相似文献
43.
L. Lidfors 《Veterinary research communications》1989,13(4):307-324
The aim of this review is to find out if getting up and lying down movements can be used as one of several parameters when evaluating different cattle environments. Getting up and lying down movements are performed according to innate movement patterns. An unsuitable environment can cause these movements to become incomplete or abnormal and so lead to injuries. Physiological measurements at lying down show a greater change in tethered cattle than in cattle kept on deep litter. In short stalls the use of certain types of tethers and the height of the manger edge affect the normal getting up and lying down movements. Unsuitably designed cubicles in loose housing systems can lead to changed movement patterns. Calves and fattening bulls have fewer lying down and getting up movements and longer lying intervals on slatted floors than on deep litter. Calves kept in small individual crates carry out a large percentage of their lying down and getting up procedures abnormally. In this review it is shown that it is possible to make improvements in the environment of cattle by using results from studies of these behaviour patterns. The conclusion is that getting up and lying down movements can be used as one of several parameters when evaluating different cattle environments. 相似文献
44.
为探讨大规模、突击性抢建公共租赁住房面临的风险,在文献研究和实际调研的基础上,利用PSD技术平台进行风险诊断,采用头脑风暴法、德尔菲法进行风险识别,层次分析法(AHP法)评估各个风险因子对公共租赁房系统风险的贡献值,研究表明:①准则层中对公共租赁房系统风险中资金风险、规划选址风险、土地供给风险、建设管理风险的贡献值分别为0.460 1,0.287 5,0.185 3,0.067 1;②确保建设资金可持续性、完善选址区域基础设施是公共租赁住房制度持续健康发展的核心与关键. 相似文献
45.
FRITH Oliver B 《中国林业科技(英文版)》2012,(Z1):20-28
The solar-powered hybrid energy system has been put into practice in Hunan bamboo culm prefabricated housing and was enrolled in this study.In this paper,the experimental data which was taken from a demonstration house highlighted that this system has a high potential for integrated solar energy utilization.The average thermal efficiency of the collector was 58.68%,and the thermal conductivity coefficient of bamboo culm prefabricated composite wall was 1.075 W/(m2 K).Based on these results,bamboo culms could be used as the main structural material and heat storage slow-release flooring in the prefabricated housing.The housing was lower in energy consuming. 相似文献
46.
47.
文章通在景观营造、植物应用等方面对天耀部和金沙洲社区进行比较分析,归纳出经济型住宅区绿化建设的基本原则和规律。总的来说,经济型住宅区的两大特点是经济性和适用性,其园林绿化建设应该结合宅旁绿地、公共绿地等布置小沙地、游戏器械、座椅及凉亭等低造价的小品和设施,为居民提供游戏场所、休息场地,增加居民之间的室外交往。 相似文献
48.
A. Heyer H. K. Andersson L. Rydhmer K. Lundstr?m 《Acta Agriculturae Scandinavica, Section A - Animal Sciences》2013,63(2):103-111
Seasonal application of once-bred gilts for piglet and meat production outdoors could be a worthwhile alternative rearing form to normal commercial production. Compared with growing/finishing pigs, payment for sow carcasses is considerably reduced because of an assumed decrease in meat quality and processing properties. The purpose of this study was to compare maiden and once-bred gilts for carcass quality, and technological and sensory meat quality. The control group of 14 gilts (LW*L and LW*D) was reared indoors and slaughtered unmated at an average live weight of 145 kg. In contrast, 38 once-bred gilts of the same breeds were initially reared like the maiden control, inseminated and then housed outdoors from one month before farrowing until slaughter. Carcass traits, technological meat quality (pH, internal and surface reflectance, water holding capacity, commercial processing yield (total yield) and laboratory processing yield (Napole yield), WB shear force and chemical composition of M. longissimus dorsi were measured. Sensory meat quality (taste panel) of oven-baked M. longissimus dorsi and cured and smoked M. semimembranosus et adductor was investigated. Carcass quality traits such as higher lean meat content and lower backfat thickness were preferable with the once-bred gilts. For technological meat quality characteristics, once-bred gilts had lower thawing loss, Napole yield, dry matter and higher total work of WB shear force and intramuscular fat, compared to maiden gilts. In general, sensory meat quality was comparable between the two groups. In processed meat only, once-bred gilts had higher juiciness and salinity and unfavourable increased stringiness, compared to maiden gilts. Thus, once-bred gilts produce valuable carcasses and are suitable for an outdoor seasonal rearing system. 相似文献
49.
E. Simensen P. S. Valle S. Vatn 《Acta Agriculturae Scandinavica, Section A - Animal Sciences》2013,63(3):194-201
Abstract Factors influencing rate of barren ewes, number of lambs born per pregnant ewe, and autumn live weight of the lambs were studied in 627 Norwegian sheep flocks based on herd level data from the Norwegian Sheep Recording System and a mailed questionnaire to the sheep farmers. The following factors were significantly associated (P<0.05) with rate of barren ewes: breed, herd average lambing date, type of production/age of farmer, routines for treatments for parasites, and housing type. Number of lambs born per pregnant ewe was significantly associated with rate of barren ewes, herd average lambing date, breed, percentage grass silage of total roughage, and no separation of gimmers during the housing period. Corrected autumn live weight of the lambs was significantly associated with breed, flock size, lambs born per pregnant ewe, no separation of gimmers during the housing period, and type of summer pasture. 相似文献
50.