长航时轻型固定翼农用遥感无人机设计与仿真     

朱航  王月  兰玉彬  张萃  李珂宇 《农业机械学报》2021,52(3):234-242

针对电动无人机应用于农业遥感监测时受其续航时间限制的问题,从实际应用角度出发,设计了一种续航时间长、适用于农业遥感监测的翼身融合布局的轻型电动固定翼无人机。提出了翼身融合布局轻型固定翼无人机的总体设计方法,确定了轻型固定翼无人机的结构参数,建立了物理模型并对其参数进行了优化分析。通过计算流体力学(Computational fluid dynamics,CFD)分析计算了翼身融合布局轻型固定翼无人机的气动性能,基于流固耦合模型动态分析了其飞行状态下的受力分布。结果表明,优化模型较初始设计模型的升阻比提高了2.6%,在迎角为6°、巡航速度为15.5 m/s时,所设计的翼身融合布局轻型固定翼无人机机身压力分布合理,且拥有良好的气动特性。起飞质量为1.5 kg时,无人机下表面压力最大,为143 Pa,升力主要集中在机翼前缘部分,计算所得理论续航时间为65 min,在巡航阶段最大变形量0.288 38 mm,符合飞行器工作条件,无人机结构和选用材料均满足设计和使用要求。本文设计的电动轻型固定翼农用遥感无人机在结构、材料和性能方面均适用于农业遥感监测。  相似文献   

Inconel 718合金的磁性复合流体抛光工艺     

Oumar Souleymane A Kiari  姜晨  高睿  张瑞 《农业装备与车辆工程》2021,(1)

针对Inconel 718合金材料加工中不断提高的表面质量需求,研究了采用磁性复合流体(Magnetic compound fluid)抛光Inconel718合金材料的加工工艺。根据磁性复合流体抛光原理搭建Inconel718合金抛光实验平台,进行不同抛光方向、抛光时间、抛光转速等工艺参数下的Inconel718合金抛光实验,对工件表面的表面粗糙度、微观形貌进行了测试与分析。实验结果表明:当抛光转速800 r/min,抛光间距3 mm,抛光时间10 min时,Inconel718合金表面粗糙度Ra下降约至0.1μm。  相似文献   

Effect of cryoprotectants, equilibration periods and freezing rates on cryopreservation of spermatozoa of mahseer, Tor khudree (Sykes) and T. putitora (Hamilton)     

Ravindragouda Patil  & Wazir Singh Lakra 《Aquaculture Research》2005,36(15):1465-1472

A study was conducted to standardize a protocol for cryopreservation of spermatozoa of the endangered mahseer, Tor khudree (Sykes) and T. putitora (Hamilton). The suitability of the cryoprotectants, dimethyl sulphoxide (DMSO) and glycerol, and the combination of the two were tested. Four equilibration periods and four freezing rates were also tested for their standardization. A combination of 9% DMSO and 11% glycerol gave significantly higher mean percentage of hatching in both T. khudree (45.59±1.86%) (control 71.08±0.59%) and T. putitora (45.00±1.25%) (control 73.48±1.19%) among the eight different treatments. Among the four different equilibration periods tested, the equilibration period of 30 min^?1 yielded the highest mean hatching percentage in T. khudree (39.46±1.94%) (control 71.70±0.61%) and T. putitora (38.28±1.06%) (control 73.11±0.82%). Freezing straws at a height of 8 cm above LN₂ surface for 10 min^?1 gave higher hatching percentages for both T. khudree (41.75±1.72%) (control 73.99±1.17%) and T. putitora (41.34±2.04%) (control 72.48±1.51%). The study reports the superior performance of the combination of DMSO and glycerol for the first time.  相似文献   

Use of two conventional staining methods to assess the acrosomal status of stallion spermatozoa     

E. E. Runcan  M. A. Pozor  G. L. Zambrano  S. Benson  M. L. Macpherson 《Equine veterinary journal》2014,46(4):503-506

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Proteomic Characterization of Equine Cerebrospinal Fluid     

Carolyn J. Broccardo  Gisela Soboll Hussey  Lutz Goehring  Paul Lunn  Jessica E. Prenni 《Journal of Equine Veterinary Science》2014

Cerebrospinal fluid (CSF) is a biofluid that is reflective of overall health. Although proteomic profiling of human CSF has been performed in the context of a variety of disease states, this report represents the first comprehensive proteomic analysis of equine CSF. A total of 320 proteins were confidently identified across six healthy horses, and these proteins were further characterized by gene ontology terms mapped in UniProt, and normalized spectral abundance factors were calculated as a measure of relative abundance. Theses results provide an optimized protocol for analysis of equine CSF and lay the groundwork for future studies involving the study of equine CSF in the context of pathogenic disease states.  相似文献   

Evaluation of Fluid Bolus Administration Rates Using Ruggedized Field Intravenous Systems     

Theodore R. Morgan 《The Forestry Chronicle》2014,25(2):204-209

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棉酚对罗非鱼（Oreochromisniloticus）离体精子毒性作用的研究     

叶继丹  富惠光等 《水产学杂志》1994,7(1):26-29

新鲜采取的尼罗罗非鱼精液在加入棉酚的精子保存液中28℃下培养。高达10mM 的乙酸棉酚也不影响精子在一小时内的存活率。罗非鱼精子的存活率在培养三小时后存活率显下降，而低浓度棉酚（25－100μM）显提高罗非鱼精子的 存活率。 本对上述实验结果进行了讨论。  相似文献   

Flavobacterium psychrophilum in rainbow trout, Oncorhynchus mykiss (Walbaum), hatcheries: studies on broodstock, eggs, fry and environment     

Madsen L  Møller JD  Dalsgaard I 《Journal of fish diseases》2005,28(1):39-47

The occurrence of Flavobacterium psychrophilum at four rainbow trout hatcheries was investigated to provide more knowledge about the reservoirs and transmission of this bacterium. Broodstock were sampled at stripping (including both unfertilized and fertilized eggs), and the offspring were then sampled at the eyed egg and fry stages. Water and surface samples (e.g. hatchery trays) were also sampled. Flavobacterium psychrophilum was found in ovarian fluid and milt, indicating that broodstock may serve as a reservoir and are latent carriers of the pathogen. Flavobacterium psychrophilum was not found on or inside eggs, but further egg studies will be necessary to elucidate the possibility of vertical transmission of the pathogen. Flavobacterium psychrophilum was isolated from water samples, but only from water that had been in close contact with farmed rainbow trout or eggs. Flavobacterium psychrophilum isolates were characterized and compared with well-characterized strains, using degradation of elastin, serotype and ribotype profiles. Different ribotypes of F. psychrophilum were found between hatcheries, but a common ribotype A was found at all four hatcheries. Different ribotypes were found in broodstock without clinical disease, whereas only a few ribotypes (mostly ribotype A) were found in diseased fry. The same ribotype A was found in broodstock, in water samples from hatchery trays and in fry, which suggests the possibility of transmission of F. psychrophilum between broodstock and offspring.  相似文献   

长吻鮠精子保存液在人工授精中的应用试验   总被引：1，自引：0，他引：1  

万全  沈保平  孙文贤  陈中华  刘映彬  吴德友  田宏生  钱克林 《水产养殖》2006,27(3):4-6

分别在安徽长江流域的无为和淮河流域的滁州进行长吻鮠的人工繁殖,使用LRH-A2、PG、混合激素B型、DOM 进行催产,从长江捕获的亲鱼立即催产,其催产率为66．67％,受精率80％-85％,经培育选择后催产率为83．33％,受精率65%- 87％。在滁州经多年培育的亲鱼催产率为100％,受精率78％-95％。精子保存液在精子保存和人工授精中使用效果良好。在冰桶内保存,20-30 h仍能保持良好的受精能力。  相似文献   

Comparative external morphology of cetacean spermatozoa   总被引：2，自引：0，他引：2  

Shoichi Kita  Motoi Yoshioka  Masaaki Kashiwagi  Satoru Ogawa  Teruo Tobayama 《Fisheries Science》2001,67(3):482-492

SUMMARY: To compare size and morphology of spermatozoa in cetaceans, sperm and epididymis samples were collected from 10 species in four families and spermatozoa were observed with phase-contrast and scanning electron microscopes. According to the average total length of the spermatozoa, the 10 species examined were classified into the following four groups in order of increasing size: (i) Baird's beaked (Ziphiidae) and Bryde's whales (Balaenopteridae); (ii) Dall's and finless porpoises (Phocoenidae); (iii) common, bottlenose, and Pacific white-sided dolphins (Delphinidae); and (iv) killer and short-finned pilot whales, and Risso's dolphin (Delphinidae). Spermatozoa head length of Bryde's whale and the finless porpoise were shorter than those of the other species. Spermatozoa head width was widest in the killer whale and thinnest in the Baird's beaked whale. The lateral aspects of sperm heads from the 10 species were characterized as the 'anterior region of the sperm head is thin and flat while the posterior region is thick.' The dorsal aspects of sperm heads were 'paddle-shaped' in Bryde's whales, 'bowling pin-shaped' in Baird's beaked whales, 'Japanese fan-shaped' in killer whales, an 'elongated ellipsoid shape' in Delphinidae except for killer whales, and 'ellipsoid shaped' in Phocoenidae. Size and morphology of the spermatozoa showed interspecific differences among the 10 species examined, which correspond to cetacean taxonomic classification.  相似文献