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排序方式: 共有45条查询结果,搜索用时 15 毫秒
1.
J R López S Núñez B Magariños N Castro J I Navas R de la Herran A E Toranzo 《Journal of fish diseases》2009,32(7):603-610
The first isolation of Tenacibaculum maritimum from wedge sole, Dicologoglossa cuneata, is reported. The pathogen was recovered from ulcers of cultured fish, from three different outbreaks. The six isolates obtained were biochemically and serologically characterized and diagnosis was confirmed by polymerase chain reaction using specific primers and partial 16S rRNA gene sequencing. The isolates constituted a homogeneous phenotypic group; however, they belong to two of the different serotypes described within this species. A virulence evaluation of the isolates using Wedge sole fry was also performed. 相似文献
2.
楔形减阻旋耕刀设计与试验 总被引:2,自引:3,他引:2
为解决旋耕整地作业阻力大、能耗高等问题,该文基于旋耕刀理论受力模型设计了一种楔形减阻旋耕刀。采用Inventor和HyperMesh软件分别创建国标旋耕刀及楔形减阻旋耕刀的三维模型和切削土壤模型,分析了楔形减阻旋耕刀的应力强度,对比了国标旋耕刀与楔形减阻旋耕刀的切削阻力。通过田间试验对比了国标旋耕刀与楔形减阻旋耕刀的扭矩、功耗与碎土率。结果表明:楔形减阻旋耕刀所受最大应力为29.49 MPa,远小于材料的屈服强度430 MPa,在保证刀身强度的前提下,与国标旋耕刀相比,楔形减阻旋耕刀质量减轻8.3%;平均切削阻力较国标旋耕刀下降10.65%。在相同工况条件下,楔形减阻旋耕刀的平均扭矩为648.916 N·m,较国标旋耕刀下降11.35%;楔形减阻旋耕刀的平均功耗为67.3kW,较国标旋耕刀下降9.29%,碎土率提高4%,耐磨性能与国标旋耕刀持平,能够达到在降低作业功耗的同时,提高耕作质量并保证刀具使用寿命。 相似文献
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使用滑楔法建立了边坡极限状态的功能函数,用中心差商近似代替对功能函数的数学求导,运用一次二阶矩法计算可靠性指标和失效概率,并使用蒙特卡洛法进行可靠性指标校核,算例计算结果表明可靠性指标对土条侧向力倾角的假定是敏感的,可靠性指标对软弱层的内摩擦角敏感性大于软弱层的内聚力和坡体重度。 相似文献
4.
压辊数量对虾料制粒机的颗粒品质有很大影响。文章分别对两压辊、三压辊结构进行分析,研究表明,两压辊制粒机较三压辊制粒机,更适宜用于虾料制粒。 相似文献
5.
Marcelino Herrera Luis Vargas-Chacoff Ismael Hachero Ignacio Ruíz-Jarabo Ana Rodiles José I. Navas & Juan M. Mancera 《Aquaculture Research》2009,40(7):790-797
Physiological responses to a high stocking density were tested in juvenile wedge sole Dicologoglossa cuneata (Moreau). Fish were kept at low (1 kg m−2 ), medium (3 kg m−2 ) and high (9 kg m−2 ) stocking densities for 22 days. No differences in the weight, length, survival and hepatosomatic index were observed among treatments. Basal plasma cortisol and osmolality were found to be directly and positively related to stocking density. A mild increase in plasma glucose was seen at medium density, and plasma protein was elevated at medium and high densities. The liver glucose and glycogen content was inversely related to stocking density. The liver triglyceride level was significantly elevated at the highest density, and the α-amino acid content decreased at the highest density. In muscle, glucose levels were significantly higher in fish kept at the lowest density; the α-amino acid content was elevated in fish kept at high density. In conclusion, plasma cortisol levels indicated an increasing stress level depending on the culture density, but significant changes in energy reserves did not occur in tissue (mainly liver and muscle glycogen and glucose reserves were significantly affected). 相似文献
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Rock masses have defects,such as joints and fractures, which are the main seepage passages.Joints and fractures often are treated as parallel plates with the seepage state kept steady and the ground stress constant. When changes take place in joints and fractures as a result of stress changes induced by excavation,joints or fractures may be wedge-shaped,and the distribution of piezometric head along the fracture will be nonlinear.A distribution function of piezometric head is suggested and compared with the results of previous research.The influence of this function on the calculation of the slope safety factor is investigated.The study shows that this function is reasonable. 相似文献
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