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11.
利用Fluent软件中修正的k—ε湍流方程及拉格朗日法的离散相模型对4ZTL—1800型割前摘脱稻麦联合收获机分离清选装置内物料运动进行了数值计算,得到了物料在分离清选装置内的运动轨迹,沉降、分离、清选等运动规律,并通过数值计算得到物料质量流量、分离装置入口气流速度和分离清选装置收集物料的清洁率的关系。 相似文献
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为解决冬季寒冷林区汽车大修车间空气污染严重问题,研究设计了节能式空气净化装置。文中论述了该装置的结构特点,设计原理,计算方法,技术参数和应用范围。 相似文献
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从生态节水理念出发,以阿克苏市红旗坡农场棉花试验基地内的2.67hm2枣园为研究对象,对枣园采取清耕与覆草措施,比较两者的水分状况,以达到节水灌溉的目的。同时对清耕与覆草措施下枣树叶水势的日、季变化规律及影响因子进行分析。结果表明,清耕与覆草措施的枣树叶水势日变化均值分别为(-1.23±0.66)MPa和(-1.14±0.60)MPa,季变化均值分别为(-1.24±0.12)MPa和(-1.17±0.10)MPa。覆草措施的枣树叶水势明显高于清耕措施,两者日变化曲线均呈单谷型,季变化均呈"V"型,这种变化规律是枣树适应该地区生境的生理特征之一。清耕与覆草措施枣树叶水势的日变化与气温、大气相对湿度、辐射照度有十分显著的相关性,季变化与土壤水势也有十分显著的相关性。清耕与覆草措施下枣树叶水势与蒸腾量也呈线性相关,土壤水势下降,蒸腾加快,叶水势降低;土壤水势上升,蒸腾减弱,叶水势回升。 相似文献
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《Scandinavian Journal of Forest Research》2012,27(6):496-504
The effect of the timing of precommercial thinning on the productivity of work was examined in young Norway spruce [Picea abies (L.) Karst.] stands in southern Finland. The common problem of large variation between sample plots in time studies was avoided by introducing a new approach based on a combination of stand measurements, tree-ring analysis and existing work productivity functions. The results indicated that a 2 year delay in the precommercial thinning of a stand was enough to cause an increase of 10-42% in the consumption of working time at a mean height of 1.5-3.1 m. At a later thinning, at a mean height 4.1-7.2 m, the increase was 8-24%. The development of the stand up to the first commercial thinning was not significantly influenced by a 2 year delay in the late precommercial thinning. 相似文献
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对深圳南山区的8个街道农贸市场、批发市场及少数市场周围地摊上销售的蔬菜农药残留污染状况进行调查,抽样检测了包括叶菜类、瓜果类、豆类、花菜类四大类蔬菜共12336份样品。结果表明:深圳南山区蔬菜的农残安全状况总体较好,各街道市售蔬菜的农残合格率达99.48%,叶菜类较其他种类蔬菜的农药残留合格率低,不同市场的蔬菜农药残留状况差异较大,正规市场的安全状况较好,市场外地摊蔬菜的农残超标率较高,达22.92%,是市场蔬菜的44倍。为保证蔬菜食用安全,市民应尽量到超市或农贸市场购买蔬菜。蔬菜经过冲洗、浸泡和漂烫处理均能显著降低蔬菜农药残留含量,考虑到经济和营养等因素,以冲洗10min、浸泡30min、漂烫1min左右为宜。 相似文献
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Salmonellosis represents an important public health concern. Several authors point out the inefficiency of the cleaning and disinfection protocols to remove the bacteria from the field. For this reason, innovative techniques, as bacteriophages, could be implemented to control the bacteria. The main objectives of this study were to assess the effect of bacteriophages against Salmonella Infantis and Salmonella Enteritidis on farm surfaces, and to evaluate bacteriophage procedure application as sanitiser against Salmonella in field conditions. Thus, most prevalent serovars in poultry production were selected (Salmonella Infantis and Salmonella Enteritidis) to contaminate farm facilities. Then, two specific bacteriophages isolated from poultry faeces were applied against them. Results showed Salmonella Infantis and Salmonella Enteritidis decreased of 4.55 log10CFU/mL and 3.85 log10CFU/mL, respectively; the maximum reduction in Salmonella was the 5th day, after 108 PFU/mL and 103 PFU/mL bacteriophage application. These results highlight bacteriophages as a promising tool together with cleaning and disinfection. 相似文献
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ShenDechao 《东北农业大学学报(英文版)》1995,2(2):142-151
In this paper the application of a cleaning system which was made up of a centrifugal fan with double channel and one sieve to 4LZ-3.5 combine was introduced.This cleaning system with double channel compared with the traditional air-sieve cleaning system of combines may omit one two sieves and simplify the transmission mechanism.It is also compared with the present cleaning systom with double channel applied to some combines,such as the Commandor 112CS/228CS combines of Claas Corporation in Germany and the MAXIMIZER^TM combines of John Deere company in U.S.A.It may omit one sieve and the precleaner and simlity the transmission mechanism.The measuring results indicated that the cleaning ratio of wheat grain is 99.1% and the cleaning loss ratio of wheat is 0.17% when the feed rate is 4.01kg/s. 相似文献
20.
Evaluation of the Efficacy of Disinfectant Footmats for the Reduction of Bacterial Contamination on Footwear in a Large Animal Veterinary Hospital
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